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SOLUTION CHEMISTRY
Crystal Clear Science!
UNIT INTRODUCTION
Solubility, dissolving rate and the role of water in solutions are important concepts in chemistry. Changing
the dissolving rate and using heat to increase the solubility of a solute in a solvent are commonly used at
home. Examples include cooking, mixing a powdered drink into water, making sun tea and even taking
medicine. A practical extension of these examples is crystal growing.
In this module, IPC teams of students grow crystals using Copper II sulfate and Aluminum Potassium
sulfate. Students measure the size and mass of their crystals daily and graph the results. Students write
in their crystal diaries every time they see their crystals to record information about the crystal and any
observations that they have made concerning the ways to grow the most perfect crystal in size and
shape. Students will conduct four experiments on water (universal solvent), temperature versus solubility,
types of solutions (saturated, unsaturated and supersaturated) and ways to change the rates of
dissolving solutes into solvents. Students will observe different crystal shapes and the different solubility
rates of the two crystal growing chemicals.
As a final activity, the crystal diary is turned into the teacher with daily entries, data tables, graphs and
answers to questions. A possible "beauty contest" can be held giving prizes to the "Most Beautiful
Crystal" of each solute, the "Best Shape" award for each solute, and if the class members can be good
humored about it: "The Most Sympathetic Crystal Award."
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TABLE OF CONTENTS
UNIT COMPONENTS
Steve’s Engaging Movie Clip
A brief description of the accompanying SCIENCE in the MOVIES DVD for this unit.
PAGE
SOLUTION
CHEMISTRY
Overview of Learning Experiences
Targeted Science TEKS, Engage, Explore, Explain, Elaborate, Evaluate
3
Unit Project Description
An exciting project focuses student learning and participation in unit activities. A
description of the project is outlined here.
4
Unit Engagement
Students participate in introductory activities to capture their interest about a
problem or phenomenon and make connections to prior knowledge and experiences.
7
Unit Exploration
Students manipulate materials during hands-on activities to explore the concept
further while sharing their observations and ideas with others.
8
Unit Explanation
Students communicate their findings from the explore activity as the teacher guides
the discussion using effective questioning strategies, introducing new terms as
appropriate, and clarifying any misunderstandings.
40
Unit Elaboration
Students apply, extend, and enhance their understanding by participating in
additional active learning opportunities.
41
Unit Evaluation
Students demonstrate their understanding of concepts. This section includes both a
performance rubric and sample TAKS items.
42
Unit Materials
List and description of items required for each section of the learning experience.
47
Background Information for Teachers
Teaching tips/Common misconceptions.
49
References
List of books, articles, and websites used by developers of this learning experience.
49
Master Copies
Student sheets and other material to be copies by teacher when using these learning
experiences in the classroom.
Science Course Module: Integrated Physics and Chemistry (IPC) 2005
STUDENT
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ENGAGE
TEKS
Overview of Learning Experiences
9 Science concepts. The student knows how solution chemistry is a part of everyday life.
The student is expected to:
(A) relate the structure of water to its function as the universal solvent;
(B) relate the concentration of ions in a solution to physical and chemical properties such as
pH, electrolytic behavior, and reactivity;
(C) simulate the effects of acid rain on soil, buildings, statues, or microorganisms;
(D) demonstrate how various factors influence solubility including temperature, pressure,
and nature of the solute and solvent; and
(E) demonstrate how factors such as particle size, influence the rate of dissolving.
See Steve's video clip for "Solution Chemistry."
Show students photos, books, web sites or video of mineral samples of crystals.
If possible, show some actual mineral crystals.
Discuss how crystals grow.
EXPLAIN
EXPLORE
EXPLORATION ACTIVITIES:
Exploration Activity One:
“Crystal Project”
(This activity should start at the beginning of the unit and be completed by the end of the
unit.)
Exploration Activity Two:
“Dissolving Rate of Sugar”
Exploration Activity Three: “Saturated Solutions”
Exploration Activity Four: “Effect of Temperature on the Solubility of KNO3”
Exploration Activity Five:
“Universal Solvent”
WHOLE GROUP DISCUSSION
What have you observed that would help you grow the most perfect shaped crystal?
What have you observed that would help you grow the largest crystal?
What hints would you give to students who were just starting out to grow a crystal?
What dissolving rate exploration activity observations apply to crystal growing?
How did temperature/solubility of a solute and the type of solution apply to growing crystals?
ELABORATE
TECHNOLOGY CONNECTIONS
Investigate crystal growing competitions on the Internet.
Create a computer slide show to show how your crystal changed over time.
Investigate other solubility graphs on the Internet to find possible crystal growing recipes.
Keep your crystal diary on the computer and print out a decorative and informative diary.
EVALUATE
FINAL PROJECT: “Crystal Project”
A film crew comes to the area to film an adventure-action movie. One scene involves valuable crystals
that will be stolen by the hero. You are hired to grow the most perfect and largest crystals possible so
that they will be filmed as part of the movie. By doing this project, students will be highly motivated to
investigate how to grow the best crystal because they are growing their own. As the unit progresses,
students will observe and formulate "hints" that will be useful. The exploration activities are designed to
help students understand the concepts of how crystals grow and be successful in their learning and their
crystal growing.
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Crystal Growing Project
PROJECT DESCRIPTON:
Students grow crystals as they learn about factors that affect solubility and dissolving, and water as
the universal solvent. Each student keeps a crystal diary and measure mass and length daily. At the
end of the project, data tables, graphs, the crystal diary entries and answers to questions are
handed into the teacher. This unit covers TEKS 9A (relate the structure of water to its function as the
universal solvent), 9B (concentration of ions), 9D (factors that affect solubility) and 9E (factors that
affect dissolving)
ACTION:
A movie team has come to the town to film an adventure-action film. A major scene of the movie
involves stealing valuable treasures and the director hires you to grow the most perfect and largest
crystals. These crystals will be featured in the film.
DESIGN CONSTRAINTS:
Materials:
•
•
•
•
•
•
•
•
•
•
•
•
•
•
two beakers,
paper to hold the chemical, balance
two burners or one hot plat
thermometer
water
chemical for the crystal
thread
splint (or popsicle stick)
sandpaper (or emery board)
empty metal coffee can
graduated cylinder
goggles
apron
wooden stirring stick for solution
Procedure (Exploration)
Split up the following jobs:
1.
Mass out your chemical. Remember to find the mass of your paper to hold the chemical. The
amount of chemical needed is: 50 grams of Copper Sulfate OR 22 grams of Potassium
Aluminum Sulfate.
2.
Measure out 100 ml of water with the graduated cylinder and pour it into a beaker.
3.
Add the chemical to the water and heat the mixture until it reaches 50 degrees Celsius. Stir
with a non-metal stick as the mixture is being heated.
4.
Make sure that the seed crystal is tied securely on a piece of thread using a slip-knot. Attach
the other end to the wooden splint. Find the mass of the seed crystal and measure its length.
Begin to write about the crystal and what you did today in your journal. This should be at least
2 sentences.
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5.
Prepare a warm water bath by heating water in the second beaker to 40 degrees Celsius. Use
about 150 ml of water for the water bath.
When the chemical and water in step 3 have been heated to 50 degrees Celsius, take the
beaker off of the heat and let the solution cool on your lab table until it reaches 40 degrees
Celsius. Only then, put your crystal into the beaker as shown below:
SOLUTION CHEMISTRY
6.
7.
8.
Pour the water for your water bath into the coffee can. Check to make sure that its temperature
is 40 degrees Celsius or less. MAKE SURE THAT YOUR WATER BATH IS COOLER THAN YOUR
SOLUTION.
Put your crystal with its beaker of solution carefully into your water bath as shown below:
9.
On Day 2, remove the crystal from the beaker and dry it off. If there are bumps on it, file them
off with your emery board (or sandpaper). Remember that the bumps will get larger but holes
will fill in over time. Measure the mass and length of your crystal. Give your crystal a name.
10.
Record in your journal and write two or more sentences about what happened today. Spill out
the water bath water and put the crystal back into the solution until the next day it is checked.
11.
Every day (or when your teacher directs), check your crystal. Measure its length and find its
mass. Write at least two sentences about your observations in your journal. Keep a chart of the
date, size and mass of your crystal. Sketch the shape and size of the crystal.
12.
When it is time to change the solution (about 5 days), pour out the solution and donate the
seed crystals on the bottom of your beaker for future crystal growers. Do steps 1-3 and 5-8
again.
DIRECTOR’S (Teacher) NOTES:
Students are allotted class time to grow crystals. They can work in a team of two or more students
based on the availability of the chemicals. Students will keep a diary chronicling their "adventures"
and including their observations. A "Beauty Contest" can be held at the end of the unit after crystal
diaries, graphs, data tables and answers to questions are handed into the teacher. A "Show and Tell"
can also be scheduled.
•
•
Potassium Aluminum Sulfate can be found in pharmacies and in chemical catalogs for a
reasonable price. Its nickname is Alum.
Copper Sulfate can be found in hardware stores and chemical catalogs. Its nickname is Blue
Stone. In large amounts it can be poisonous, but it tastes so bad (like chewing on a tin can) that
students are very careful. Do not use a metal nail file to file down bumps on this crystal. It will
cause a yellow residue and cause the crystal to discolor.
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•
•
•
•
•
•
•
•
•
•
Crystal Clear Science
Students must wash their hands completely after touching their crystals. Wearing goggles and
aprons during the heating of the solutions is required.
This project should be done in teams due to the cost of supplies and the amount of work that
must be done in a short amount of time on Day 1.
Students should not ignore deformities in their crystal shapes. Holes will fill in over time but
bumps on the crystal shape will get larger over time.
Coffee cans work well for holding the water bath water, but any waterproof container with a flat
bottom will work. Make sure that the beaker of solution does not float in the water bath. If the
beaker falls over, the crystal will dissolve.
On Day 2, some students will find that their crystals have grown nicely. Some teams will find an
empty loop. This is usually caused by a solution temperature above 40 degrees at the time that
the crystal was added, water bath at a higher temperature than 40 degrees, too much water
added to the solution or too little chemical. Sometimes, the students have tied the seed crystal
too loosely and it fell to the bottom of the beaker.
If there is solute on the bottom of the solution, the saturated solution is safe to hang another
seed crystal. Notching the crystal to give the string a place to settle will often prevent the crystal
from slipping out. This new crystal will grow slowly by evaporation and has missed the cooling
part of crystal growing until next time the solution is changed. Hang the crystal low in the
solution. If there is no solute on the bottom of the beaker, this unsaturated solution is unsafe for
a seed crystal. If the teacher has extra solution from the demonstration day, some can be added
to an empty beaker. If not, students may need to come on their own time to repeat the
experiment.
After the first day, the water bath can be spilled out unless the room where it is stored gets very
hot. The water bath will keep the solution at a constant temperature and prevent the dissolving
of the crystal by heated water molecules.
Teacher can show students atomic structures of different mineral crystals.
At the end of the crystal growing, a "beauty contest" can occur. Students can vote for "Most
Beautiful", "Best Shape", "Most Sympathetic" crystal awards. Prizes (such as rock candy) and
certificates can be given out.
If there is a yellow residue on the crystal, wash it off. This is due to a reaction to metal such as
metal stirring rod or metallic ions in the water. If the solution is contaminated, pour it out and
clean the beaker completely.
Change the solution at least once during this project. Five days between new solutions is best.
Students should give the teacher the seed crystals so they can be used next year.
The last recommendation is for the teacher to try this project ahead of time. In this way, sample
crystals will available for students to see and there will be a supply of seed crystals for students to
use. Good Copper sulfate crystals look like parallelograms and good Alum crystals look like flat
diamonds. The teacher can also anticipate problems so that all students will be prepared to complete
this project successfully.
SAFETY NOTE: Be careful using chemicals. Make sure students wash hands thoroughly.
Students must wear goggles and aprons for safety. Students must not taste chemicals or
rub their eyes with unwashed hands.
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ENGAGE
ENGAGE
Show large scale photos, pictures, web sites or actual
mineral crystals to discuss the formation of crystals in
nature.
Discuss how to grow crystals and include the properties of
solutes and solvents. Share the process to grow crystals.
Go directly to “Growing Crystal Project” and have students
start their crystal growing.
SHOW STEVE’S
Solution
Chemistry clips
to engage
students in the
study of
crystals.
I Get to Grow a Crystal!
Watch an Engaging Film Clip!
Show large sized crystals of Copper II sulfate and
Aluminum Potassium sulfate grown by teacher before the
unit begins.
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Students participate in five exploration activities:
Exploration Activity One: Crystal Growing Project"
Let DO Science !
Students investigate solution chemistry and learn that the
rate of dissolving and amount of a solute dissolved by a
solvent depends on the nature of each, the temperature
and particle size. They gain this knowledge by growing
crystals that are of high personal interest.
Students explore
the concept of
solutions and
participate in four
activities in which
investigate factors
that affect
solubility, rate of
dissolving and
water as the
universal solvent.
EXPLORE
Explore
Exploration Activity Two: "Dissolving Rate"
Students investigate which factors most affect the
dissolving rate of sugar. Students will discover that surface
area, temperaturem, and sturring or shaking are all
afctors that affect the dissolving rate of a solute.
Exploration Activity Three: "Saturated Solutions"
In this investigation, students will learn that unsaturated solutions
have solvents that have not dissolved all of the solute possible at
that temperature. They will learn that solutions become saturated
when the solvent has dissolved all of the solute possible at that
temperature. Supersaturated solutions occur when the solvent
cools and is still holding more solute that it normally holds at that
temperature. Students will observe that supersaturated solutions
can drop the extra solute with help (like shaking) and the solute
drops until the solution becomes saturated.
Exploration Activity Four: "Effect of Temperature on
Let’s DO Science!
Solubility”
In this lab students study the effect of temperature on the
solubility of KNO3 . When given different temperatures
students will be able to explain the effect of increased
temperature on the solubility of KNO3. Students will graph
their data and will be able to determine the solubility of
various solutes at a given temperature.
Exploration Activity Five: "Universal Solvent"
Students investigate the properties of water and learn that water's
structure allows it to dissolve many substances and is therefore
known as the universal solvent.
Science Course Module: Integrated Physics and Chemistry (IPC) 2005
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IPC: Science Course Module—Goes to the Movies! University of Houston
Growing Crystals
Type of Lesson:
IPC Content TEKS:
Content with Process: Focus on constructing knowledge through active learning.
9A
9D
9E
1.
2.
3.
Learning Goal/
Instructional
Objective:
Relate the structure of water to its function as the universal solvent.
Demonstrate how various factors influence solubility including
temperature, pressure and the nature of the solute and solvent.
Demonstrate how factors such as particle size influence the rate of
dissolving.
General Objective
Students investigate solution chemistry and learn that the rate of dissolving and amount of a
solute dissolved by a solvent depends on the nature of each, the temperature and particle size.
They gain this knowledge by growing crystals that are of high personal interest.
Instructional Objectives
While participating in a crystal growing project students:
1.
Explain the function of a solute and solvent in forming a solution.
2.
Point out that for many solute/solvent combinations, as the temperature
increases, the solubility of solute increases, as does the dissolving rate. Also, to
identify the solubility of rate of a solute/solvent from a line graph.
3.
Discuss that as the surface area of solutes increases and the particle size
exposed to the solvent decreases, the dissolving rate increases.
4.
Observe and describe that different solutes, such as potassium aluminum sulfate
and copper sulfate have different solubilities.
5.
Construct and interpret graphs showing how the change in mass and size of
crystals result over time.
6.
From daily observations of crystal growth, describe how as a crystal solution
cools, the solvent drops extra solute to form crystals. Also, as the solvent
evaporates how this contributes to the formation of crystals.
7.
Identify solutions that are unsaturated, saturated, and supersaturated.
8.
Grow large, well-formed crystals.
Key Question:
Why do crystals grow? What factors affect the growth of the crystal?
Related Process TEKS:
(1) Scientific
processes.
The student, for
at least 40% of
instructional
time, conducts
field and
laboratory
investigations
using safe,
environmentally
appropriate, and
ethical practices
The student is expected to:
(A) demonstrate safe practices during field and laboratory investigations; and
(2) Scientific
The student is expected to:
(B) make wise choices in the use and conservation of resources and the
disposal or recycling of materials.
Science Course Module: Integrated Physics and Chemistry (IPC) 2005
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processes.
The student uses
scientific
methods during
field and
laboratory
investigations.
Crystal Clear Science
(A) plan and implement experimental procedures including asking questions,
formulating testable hypotheses, and selecting equipment and technology;
(B) collect data and make measurements with precision;
(C) organize, analyze, evaluate, make inferences, and predict trends from
data; and
(D) communicate valid conclusions.
(3) Scientific
processes.
The student uses
critical thinking
and scientific
problem solving
to make
informed
decisions.
The student is expected to:
(A) analyze, review, and critique scientific explanations, including hypotheses
and theories, as to their strengths and weaknesses using scientific evidence
and information;
(B) draw inferences based on data related to promotional materials for
products and services;
(C) evaluate the impact of research on scientific thought, society, and the
environment;
(D) describe connections between physics and chemistry and future careers;
and
(E) Research and describe the history of physics, chemistry, and contributions
of scientists.
To the Teacher:
•
Potassium Aluminum Sulfate can be found in pharmacies and in chemical catalogs for a
reasonable price. Its nickname is Alum.
•
Copper Sulfate can be found in hardware stores and chemical catalogs. Its nickname is Blue
Stone. In large amounts it can be poisonous, but it tastes so bad (like chewing on a tin can)
that students are very careful. Do not use a metal nail file to file down bumps on this crystal.
It will cause a yellow residue and cause the crystal to discolor.
•
Students must wash their hands completely after touching their crystals. Wearing goggles
and aprons during the heating of the solutions is required.
This project should be done in teams due to the cost of supplies and the amount of work that
must be done in a short amount of time on Day 1.
•
•
Students should not ignore deformities in their crystal shapes. Holes will fill in over time but
bumps on the crystal shape will get larger over time.
•
Coffee cans work well for holding the water bath water, but any waterproof container with a
flat bottom will work. Make sure that the beaker of solution does not float in the water bath.
If the beaker falls over, the crystal will dissolve.
•
On Day 2, some students will find that their crystals have grown nicely. Some teams will find
an empty loop. This is usually caused by a solution temperature above 40 degrees at the time
that the crystal was added, water bath at a higher temperature than 40 degrees, too much
water added to the solution or too little chemical. Sometimes, the students have tied the seed
crystal too loosely and it fell to the bottom of the beaker.
•
If there is solute on the bottom of the solution, the saturated solution is safe to hang another
seed crystal. Notching the crystal to give the string a place to settle will often prevent the
crystal from slipping out. This new crystal will grow slowly by evaporation and has missed the
cooling part of crystal growing until next time the solution is changed. Hang the crystal low in
the solution. If there is no solute on the bottom of the beaker, this unsaturated solution is
unsafe for a seed crystal. If the teacher has extra solution from the demonstration day, some
can be added to an empty beaker. If not, students may need to come on their own time to
repeat the experiment.
•
After the first day, the water bath can be spilled out unless the room where it is stored gets
very hot. The water bath will keep the solution at a constant temperature and prevent the
Science Course Module: Integrated Physics and Chemistry (IPC) 2005
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dissolving of the crystal by heated water molecules.
•
Teacher can show students atomic structures of different mineral crystals.
•
At the end of the crystal growing, a "beauty contest" can occur. Students can vote for "Most
Beautiful", "Best Shape", "Most Sympathetic" crystal awards. Prizes (such as rock candy) and
certificates can be given out.
•
If there is a yellow residue on the crystal, wash it off. This is due to a reaction to metal such
as metal stirring rod or metallic ions in the water. If the solution is contaminated, pour it out
and clean the beaker completely.
•
Change the solution at least once during this project. Five days between new solutions is
best. Students should give the teacher the seed crystals so they can be used next year.
•
Multiple Intelligences:
The last recommendation is for the teacher to try this project ahead of time. In this way,
sample crystals will available for students to see and there will be a supply of seed
crystals for students to use. Good Copper sulfate crystals look like parallelograms and
good Alum crystals look like flat diamonds. The teacher can also anticipate problems so
that all students will be prepared to complete this project successfully.
LogicalMathematical
Intelligence
Consists of the ability to detect patterns, reason deductively and think
logically. This intelligence is most often associated with scientific and
mathematical thinking.
Linguistic
Intelligence
Involves having a mastery of language. This intelligence includes the ability to
effectively manipulate language to express oneself rhetorically or poetically. It
also allows one to use language as a means to remember information.
Includes interpersonal feelings and intentions of others.
Interpersonal
Intelligence
Intrapersonal
Intelligence
Intrapersonal intelligence--the ability to understand one's own feelings and
motivations.
Materials:
•
•
•
•
•
•
•
•
•
•
•
•
•
•
two beakers,
paper to hold the chemical, balance
two burners or one hot plat
thermometer
water
chemical for the crystal
thread
splint (or popsicle stick)
sandpaper (or emery board)
empty metal coffee can
graduated cylinder
goggles
apron
wooden stirring stick for solution
SAFETY NOTE:
Be careful using chemicals. Make sure students wash hands thoroughly. Students must wear safety goggles
and aprons. Students must not taste chemicals or rub their eyes with their unwashed hands. See Texas
Science Safety Manual for lab and investigation guidelines:
http://www.tenet.edu/teks/science/safety/safety_manual.html
E
ngagement: Show students pictures of mineral crystals or bring in real samples. Another motivation could be showing
students large examples of the crystals being grown
Science Course Module: Integrated Physics and Chemistry (IPC) 2005
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Explore:
Procedure: Split up the following jobs:
2.
Mass out your chemical. Remember to find the mass of your paper to hold the chemical. The amount of chemical
needed is: 50 grams of Copper Sulfate OR 22 grams of Potassium Aluminum Sulfate.
2.
Measure out 100 ml of water with the graduated cylinder and pour it into a beaker.
3.
Add the chemical to the water and heat the mixture until it reaches 50 degrees Celsius. Stir with a non-metal stick as
the mixture is being heated.
4.
Make sure that the seed crystal is tied securely on a piece of thread using a slip-knot. Attach the other end to the
wooden splint. Find the mass of the seed crystal and measure its length. Begin to write about the crystal and what you
did today in your journal. This should be at least 2 sentences.
5.
Prepare a warm water bath by heating water in the second beaker to 40 degrees Celsius. Use about 150 ml of water for
the water bath.
6.
When the chemical and water in step 3 have been heated to 50 degrees Celsius, take the beaker off of the heat and let
the solution cool on your lab table until it reaches 40 degrees Celsius. Only then, put your crystal into the beaker as
shown below:
7.
8.
Pour the water for your water bath into the coffee can. Check to make sure that its temperature is 40 degrees Celsius
or less. MAKE SURE THAT YOUR WATER BATH IS COOLER THAN YOUR SOLUTION.
Put your crystal with its beaker of solution carefully into your water bath as shown below:
9.
On Day 2, remove the crystal from the beaker and dry it off. If there are bumps on it, file them off with your emery
board (or sandpaper). Remember that the bumps will get larger but holes will fill in over time. Measure the mass and
length of your crystal. Give your crystal a name.
10.
Record in your journal and write two or more sentences about what happened today. Spill out the water bath water and
put the crystal back into the solution until the next day it is checked.
11.
Every day (or when your teacher directs), check your crystal. Measure its length and find its mass. Write at least two
sentences about your observations in your journal. Keep a chart of the date, size and mass of your crystal. Sketch the
shape and size of the crystal.
12.
When it is time to change the solution (about 5 days), pour out the solution and donate the seed crystals on the bottom
of your beaker for future crystal growers. Do steps 1-3 and 5-8 again.
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Explain:
1.
2.
3.
4.
5.
6.
Draw a graph showing how the mass of the crystal has changed during time
Draw a second graph showing how the size has changed during time.
Make sure that your data table is complete.
Your journal must have the diary entries for each day and sketches of your crystal.
You must discuss the following questions at the end of your journal entries:
A.
What problems did you have during the project? How did you solve them?
B.
Why was the water bath in the coffee can needed only on the day the solution was heated? The water bath
slowly cooled down the solution so that the solute had time to arrange onto the seed crystals. The slower a
crystal grows, the better its shape. If the water bath had not been used, the seed crystal would have grown
too quickly and the shape would have been poor. After it cooled to room temperature, the crystal was
growing by the evaporation of the solute.
C.
How did the solubility of your chemical change as the water was heated and then cooled? As the solvent was
heated, its solubility increased as more solute was dissolved by the solvent. When the solvent was cooled,
its solubility decreased and solute starts to fall out of the solution.
D.
Under which conditions could your crystal become smaller while in the beaker of solution? Explain why each
would happen and how you could "fix" each problem. My crystal can become smaller if I put it into a solution
that is too hot and the solvent dissolves the solute (crystal) because the solution is unsaturated. It can also
dissolve if there is too much solvent and the solution is unsaturated. In both cases, adding additional solute
until the solution becomes saturated will keep more of the crystal from dissolving.
E.
Do all chemicals have crystals of the same shape? Suggest reasons to explain why. Not all crystals have the
same shape. In this project, the Alum crystals look like diamonds while the Copper sulfate crystals look like
parallelograms with slanted sides. The molecules must fit differently in each solute crystal. It must depend
on the atoms of the different elements that make up each solute compound and the bonding involved.
F.
How would you improve what you have done in this project to produce a better crystal?
Write a conclusion by writing your final answer to the problem using what you have observed in this project.
Elaborate:
Investigate different minerals and their crystal shapes and colors.
Research different crystal shapes and find examples of minerals with those shapes.
Visit a local museum that features minerals.
Investigate other crystal growing chemicals besides Copper II sulfate and Aluminum Potassium sulfate.
Create solubility graphs by using other chemicals besides KNO3.
Conduct the Magic Garden Elaboration Activity found in this unit's materials.
Use solubility graph question sheet to practice reading and interpreting graphs.
E
valuate:
Explain how your students demonstrate their new understandings and skills. What is the learning product for this lesson? Is
the experimental conclusion, a picture, a Power Point presentation, a story, a solved problem? Be explicit here. And then
prepare a rubric to evaluate student learning. Be extra sure that your assessment measures exactly what the target TEKS
says it should measure.
Grading Rubric:
1. There was a diary entry for each day that students checked their crystals. ____
2. Each day, student measured the mass and size of the crystal. ______
3. There were data tables and graphs. ______
4. Sketches of the crystal over time were included. ____
5. The analysis questions (Student lab instructions #13 E 1-6) were discussed fully. ___
6. A conclusion was written that showed that the student analyzed the factors that affect crystal growth and how crystals
grow. ____
Science Course Module: Integrated Physics and Chemistry (IPC) 2005
13
sE
SOLUTION CHEMISTRY
POINTS
Scientific
Accuracy
of data and
graphs
Reasoning
4
All graphs and
data tables are
correctly set up
All questions on
crystal growing are
answered correctly
using observations
3
Graphs and data
tables set up with
some mistakes
Most questions on
crystal growing are
answered correctly
using observations
2
Graphs and data
tables set up with
many mistakes.
Some questions on
crystal growing are
answered correctly
using observations
1
Graphs and data
tables not set up
or set up
incorrectly
Subtotal: ____
Questions on
crystal growing are
unanswered or not
based on valid
observations
Crystal Clear Science
Communication in
written crystal diary
Collaboration
during crystal
growing
Crystal diary was well
organized with all
requirements met. All
questions answered
clearly and completely
Crystal diary was
organized adequately
with most requirements
met. Most questions
answered fully
Crystal diary was
slightly disorganized
with some
requirements met.
Some questions
answered
Crystal diary was
disorganized with few
requirements met. Very
few questions answered
and most is unclear and
incomplete
Team of students
worked very well
together and shared
all responsibilities and
input
Team of students
worked well together
and shared most
responsibilities and
input
Team worked
somewhat well
together. Each person
had some
responsibilities and
some input.
Team did not work
together. The team
did not share
responsibilities or
value the input of
team members
Subtotal: ____
Subtotal: ____
Subtotal: ____
TOTAL:
____/16pts
References/Resources/Websites:
•
http://www.chemistry.co.nz/crystals_defined.htm
•
•
•
•
http://uk.geocities.com/magoos_universe/crystals.htm
http://www.sdnhm.org/kids/minerals/grow-crystal.html (San Diego Natural History Museum)
http://webphysics.davidson.edu/alumni/MiLee/JLab/crystallography_
http://www.phschool.com/science/science_news/chemistry/properties_matter.html
The following site contains teacher resource lessons:
http://visualclutter.com/Links/Science
The following sites contain information about growing crystals in unusual gravity conditions:
•
http://science.nasa.gov/headlines/y2001/ast11dec_1.htm
(crystals in outer space)
•
http://www.mos.org/cst/article/77/3.html
(growing crystals in near zero gravity)
The following sites contain information about many I.P.C. topics including chemistry and crystals:
•
•
•
http://www.thinkquest.org/library/cat_show.html?cat_id=36
http://www.sciencenews.org
(This web site has advertisements.)
http://www.phschool.com/science/science_news/chemistry/properties_matter.html
Properties of Matter:
The following sites contain information about chemistry especially matter and crystals:
•
http://www.phschool.com/science/science_news/chemistry/properties_matter.html
•
•
•
•
http://www.chem4kids.com
http://www.school-for-champions.com/science.htm
http://www.thinkquest.org/library/cat_show.html?cat_id=36
http://school.discovery.com/lessonplans/physci.html
Science Course Module: Integrated Physics and Chemistry (IPC) 2005
14
sE
SOLUTION CHEMISTRY
Crystal Clear Science
IPC: Science Course Module—Goes to the Movies!
University of Houston
Dissolving Rate of Sugar
Type of Lesson:
IPC Content TEKS:
Content with Process: Focus on constructing knowledge through active learning.
9D
demonstrate how various factors influence solubility including temperature,
pressure and the nature of the solute and the solvent.
9E
demonstrate how factors such as particle size influence the rate of dissolving
Learning Goal/
Instructional
Objective:
Learning goal: Students investigate which factors most affect the dissolving rate of sugar.
Key Question:
Which factor is the most effective in dissolving sugar the fastest: temperature, particle size due to
surface area or stirring?
Related Process TEKS:
(1) Scientific
processes.
The student, for
at least 40% of
instructional
time, conducts
field and
laboratory
investigations
using safe,
environmentally
appropriate, and
ethical practices
The student is expected to:
(A) demonstrate safe practices during field and laboratory investigations; and
(2) Scientific
processes.
The student uses
scientific
methods during
field and
laboratory
investigations.
The student is expected to:
(A) plan and implement experimental procedures including asking questions,
formulating testable hypotheses, and selecting equipment and technology;
Instructional Objectives:
Students will be able to:
1. explain how changing the surface area affects the speed of dissolving
2. discuss how temperature affects the dissolving rate
3. observe how stirring affects the rate of sugar dissolving
4. identify the independent variable, dependent variable and the constants in each part of the
experiment
(B) make wise choices in the use and conservation of resources and the
disposal or recycling of materials.
(B) collect data and make measurements with precision;
(C) organize, analyze, evaluate, make inferences, and predict trends from
data; and
(D) communicate valid conclusions.
(3) Scientific
processes.
The student uses
critical thinking
and scientific
The student is expected to:
(A) analyze, review, and critique scientific explanations, including hypotheses
and theories, as to their strengths and weaknesses using scientific evidence
and information;
Science Course Module: Integrated Physics and Chemistry (IPC) 2005
15
sE
SOLUTION CHEMISTRY
problem solving
to make
informed
decisions.
Crystal Clear Science
(B) draw inferences based on data related to promotional materials for
products and services;
(C) evaluate the impact of research on scientific thought, society, and the
environment;
(D) describe connections between physics and chemistry and future careers;
and
(E) Research and describe the history of physics, chemistry, and contributions
of scientists.
To the Teacher:
INTRODUCTION:
Students conduct a variety of simple investigations to determine which factors most affect the
dissolving rate of sugar. After the various investigations, they draw conclusions from the data
they collected. The data should indicate the warmer water, crushed particles, and stirred
solutions will dissolve faster. The water temperature and stirring are common answers among the
students. You might have to have brief math lesson to review surface area. As the surface area
increases, the ability to dissolve the sugar faster. The water needs to come in contact with the
sugar to dissolve faster. The smaller particles expose more surface area allowing more water to
come in contact with the sugar.
Check the glassware for cracks before students use them on the hot plate. If a beaker has a
crack, it might break further and cause damage. Remind students to use heat resistant gloves to
remove the hot beakers from the hot plate. The directions tell them to remove the beaker from
the heat before placing the sugar in the water. If the sugar is placed in the beaker on the hot
plate, the sugar will cook and create a strong odor.
Multiple Intelligences:
LogicalMathematical
Intelligence
Consists of the ability to detect patterns, reason deductively and think
logically. This intelligence is most often associated with scientific and
mathematical thinking.
Linguistic
Intelligence
Involves having a mastery of language. This intelligence includes the ability to
effectively manipulate language to express oneself rhetorically or poetically. It
also allows one to use language as a means to remember information.
Includes interpersonal feelings and intentions of others.
Interpersonal
Intelligence
Intrapersonal
Intelligence
Intrapersonal intelligence--the ability to understand one's own feelings and
motivations.
Materials:
•
•
•
•
•
•
goggles
50-mL graduated cylinder
250-mL beaker
hot plate
alcohol thermometer
heat resistant gloves
•
stop watch (2 if possible)
•
•
•
•
•
•
apron
triple beam balance
water
6 sugar cubes
stirring rod/spoon
2 clear cups or 100 mL beakers
SAFETY NOTE:
Wear goggles and aprons for the entire lab. Use heat resistant gloves to handle hot glassware. Inspect
all glassware for cracks. Be careful of the hot plate cord and the electrical outlet. See Texas Science
Safety Manual for lab and investigation guidelines:
http://www.tenet.edu/teks/science/safety/safety_manual.html
Science Course Module: Integrated Physics and Chemistry (IPC) 2005
16
sE
SOLUTION CHEMISTRY
Engagement:
Crystal Clear Science
Discuss stomach remedies and how to speed up the time so that the medicine works faster in your stomach.
Explore:
Procedure
1. Safety goggles and laboratory aprons should be worn throughout this experiment.
2.
Obtain laboratory materials. READ THE LAB COMPLETELY THROUGH BEFORE BEGINNING.
3.
Measure 50 mL of water and place in a 100 mL beaker. Make sure there are no cracks or chips in the glass before you
place the beaker on the hot plate and turn it to high. Bring to a boil. Continue reading as the water warms. Measure 50
mL of water and place in a 100 mL beaker of water. This will be your cold water sample.
On one paper towel, carefully crush a sugar cube and label it A. Repeat the process for cube 2 labeling it B. Measure the
mass of the sugar cubes separately and record the results in the appropriate data table in your journal.
4.
5.
Once the water reaches the boiling point, use heat resistant gloves to carefully remove the beaker and set on the table.
Do not add the sugar when the water is on the hot plate.
6.
Place the crushed sugar sample A in the hot water and time how long it takes for the sugar to completely dissolve using a
stop watch. Do not shake or stir the solution. Record your observations in your data table in your journal.
COLD –
HOT
NOT STIRRED
COLD –
STIRRED
7.
Rinse out all cups and prepare for the next set. Read the data tables for Sets 2 – 4 and conduct the investigations
needed to complete the data tables.
8.
Once you are completely finished, WASH each beaker out and dry.
9.
Carefully return all materials to materials area, make sure your hot plate is unplugged, and return goggles and folded
apron. Wipe off your work area so it is clean of sugar and water.
Science Course Module: Integrated Physics and Chemistry (IPC) 2005
17
sE
SOLUTION CHEMISTRY
Crystal Clear Science
Explain:
DATA/OBSERVATIONS:
COPY THE FOLLOWING DATA TABLES BELOW IN YOUR JOURNAL TO COMPLETE AS YOU WORK.
Cup
Sugar Sample
SET
1
A
Mass (g)
Time (min.)
faster
Sugar Sample
Cube
Cube
Water Conditions
Hot
Cold
Time (min.)
faster
Cup
E
F
Sugar Sample
Cube
Cube
Water Conditions
Hot, stirred
Hot, NOT stirred
Mass (g)
Time (min.)
faster
Sugar Sample
Water Conditions
Cup
G
Crushed
Cold, stirred
H
Crushed
Cold, NOT stirred
ANALYSIS/CONCLUSIONS: (Record in your journal.)
Mass (g)
Time (min.)
faster
SET
4
Cup
C
D
Mass (g)
SET
2
Cold
SET
3
B
Crushed
Crushed
Water Conditions
Hot
1.
Did you change the same factors in each set?
variable in each set.
yes
Independent Variable
Set
2.
Complete the data table below identifying the independent
1
Temperature
2
3
4
Temperature
Stirred
Stirred
Were all the dependent variables the same?
variable for each set.
yes
Complete the data table below identifying the dependent
Dependent Variable
Set
1
Time
2
Time
Science Course Module: Integrated Physics and Chemistry (IPC) 2005
18
sE
SOLUTION CHEMISTRY
3
4
3.
Crystal Clear Science
Time
Time
Complete the data table below identifying the constants for each set.
Constants
Set
1
Solute, particle size, amount of water, not stirred
Solute, particle size, amount of water, not stirred
Solute, temperature, particle size, amount of water
Solute, temperature, particle size, amount of water
2
3
4
4.
How does the particle size affect the rate at which sugar dissolves in water? The smaller the particle the faster it
dissolves.
5.
How does temperature affect the rate at which sugar dissolves in water? The higher the temperature, the faster the
sugar dissolves.
6.
How does stirring affect the rate at which sugar dissolves in water? Stirring causes the particles to move faster and break
up faster causing the sugar to dissolve faster.
7.
If you wanted to dissolve a substance faster, what should you do? Heat the water, stir the solution, and crush the solute.
8.
If you wanted to dissolve a larger amount of substance, say 10 sugar cubes, what should you do to dissolve the sugar
faster? Heat the water, stir the solution, and crush the solute.
Elaborate:
1.
2.
3.
Based on lab observations, investigate the effect of surface area and particle size on starting a fire with wood.
Find out examples of how cooking uses the observations on the effect of particle size (surface area), and stirring on
the rate of dissolving AND solubility affected by temperature, pressure and the nature of the solute and solvent.
Apply all of the lab observations to crystal growing.
E
valuate:
Students evaluate and analyze data and observations. Based on data and observations, students complete questions and
relate their observations to real life experiences
Grading Rubric:
POINTS
Scientific
Accuracy
4
All data was
collected
accurately.
3
2
Most data was
collected
accurately.
Some data was
collected
accurately.
Reasoning
Communication
Collaboration
Conclusions were
correctly reached
using accurate
data and other
observations.
Most conclusions
were correctly
reached using
accurate data and
other observations.
Data was displayed
properly with correct
units. All questions
were answered clearly
and with detail.
Most data was
displayed properly with
most units correct.
Most questions were
answered clearly and
with detail.
Some data was
displayed properly with
some correct units.
Some questions were
answered clearly with
some detail.
Team worked well
together. All team
members contributed
and discussed lab
results in detail.
Team worked fairly
well together. Most
team members
contributed and there
was some discussion
of lab results.
Team did not always
work well together.
Some team members
worked together and
there was little
discussion of lab
results.
Based on accurate
data and
observations,
conclusions were
incorrectly
reached.
Science Course Module: Integrated Physics and Chemistry (IPC) 2005
19
sE
SOLUTION CHEMISTRY
1
Data was
inaccurate
Subtotal: ____
Crystal Clear Science
Conclusions were
incorrect.
Data was improperly
displayed with incorrect
units. Few questions
were answered clearly
with little detail.
Team worked poorly
together. Team
members did not help
each other or discuss
the lab results.
Subtotal: ____
Subtotal: ____
Subtotal: ____
TOTAL:
____/16pts
References/Resources/Websites:
•
http://www.chemistry.co.nz/crystals_defined.htm
•
•
•
•
http://uk.geocities.com/magoos_universe/crystals.htm
http://www.sdnhm.org/kids/minerals/grow-crystal.html (San Diego Natural History Museum)
http://webphysics.davidson.edu/alumni/MiLee/JLab/crystallography_
http://www.phschool.com/science/science_news/chemistry/properties_matter.html
The following site contains teacher resource lessons:
http://visualclutter.com/Links/Science
The following sites contain information about growing crystals in unusual gravity conditions:
http://science.nasa.gov/headlines/y2001/ast11dec_1.htm
(crystals in outer space)
•
•
http://www.mos.org/cst/article/77/3.html
(growing crystals in near zero gravity)
The following sites contain information about many I.P.C. topics including chemistry and crystals:
•
•
•
http://www.thinkquest.org/library/cat_show.html?cat_id=36
http://www.sciencenews.org
http://www.phschool.com/science/science_news/chemistry/properties_matter.html
Properties of Matter:
The following sites contain information about chemistry especially matter and crystals:
•
http://www.phschool.com/science/science_news/chemistry/properties_matter.html
•
•
•
•
http://www.chem4kids.com
http://www.school-for-champions.com/science.htm
http://www.thinkquest.org/library/cat_show.html?cat_id=36
http://school.discovery.com/lessonplans/physics.html
Science Course Module: Integrated Physics and Chemistry (IPC) 2005
20
sE
SOLUTION CHEMISTRY
Crystal Clear Science
IPC: Science Course Module—Goes to the Movies!
University of Houston
Saturated Solutions!
Content with Process: Focus on constructing knowledge through active learning.
Type of Lesson:
IPC Content TEKS:
8B
9D
Analyze energy changes.
Demonstrate how various factors influence solubility including temperature,
(pressure), and nature of the solute and solvent.
9E
Learning Goal/
Instructional
Objectives:
Demonstrate how factors (such as particle size) influence the rate of
dissolving.
In this investigation, students learn that unsaturated solutions have solvents that have not dissolved all of the
solute possible at that temperature. They learn that solutions become saturated when the solvent has dissolved
all of the solute possible at that temperature. Supersaturated solutions occur when the solvent cools and is still
holding more solute that it normally holds at that temperature. Students will observe that supersaturated
solutions can drop the extra solute with help (like shaking) and the solute drops until the solution becomes
saturated.
Instructional Objectives:
•
When observing solutions, students can distinguish between unsaturated, saturated and
supersaturated solutions.
•
When observing solutions, students can determine the effect of the temperature on the rate of
dissolving and solubility of solute.
•
When observing crystallization, students explain the temperature changes.
Key Question:
Related Process TEKS:
What are the differences between unsaturated, saturated and supersaturated solutions?
(1) Scientific
processes.
The student, for at
least 40% of
instructional time,
conducts field and
laboratory
investigations using
safe,
environmentally
appropriate, and
ethical practices
(2) Scientific
processes.
The student uses
scientific methods
during field and
laboratory
investigations.
The student is expected to:
(A) demonstrate safe practices during field and laboratory investigations; and
(B) make wise choices in the use and conservation of resources and the
disposal or recycling of materials.
The student is expected to:
(A) plan and implement experimental procedures including asking questions,
formulating testable hypotheses, and selecting equipment and technology;
(B) collect data and make measurements with precision;
(C) organize, analyze, evaluate, make inferences, and predict trends from data; and
(D) communicate valid conclusions.
(3) Scientific
processes.
The student uses
critical thinking and
scientific problem
solving to make
informed decisions.
The student is expected to:
(A) analyze, review, and critique scientific explanations, including hypotheses and
theories, as to their strengths and weaknesses using scientific evidence and information;
Science Course Module: Integrated Physics and Chemistry (IPC) 2005
21
sE
SOLUTION CHEMISTRY
Crystal Clear Science
To the Teacher:
1. The chemical Sodium thiosulfate (Hypo) can be purchased from chemical catalogs.
2. Use a disposable container to collect the Hypo solution after the experiment is completed.
3. If students are observant, they will notice that the test tube gets colder as the Hypo is
dissolved in the water and after the Hypo falls out of the supersaturated solution, the test tube
will get warmer.
4. To see the supersaturated solution "snow", the solution should be clear when lifted out of the
cold water beaker and as the crystals are dropped in, the test tube must be shaken sideways. Be
careful that the solution does not splash out.
5. The supersaturated solution will stop dropping Hypo crystals until it becomes saturated.
6. Make sure that the students re-heat the test tubes to completely dissolve the chemical. If not,
the test tubes are very difficult to clean out.
Multiple Intelligences:
LogicalMathematical
Intelligence—
Consists of the ability to detect patterns, reason deductively and think
logically. This intelligence is most often associated with scientific and
mathematical thinking.
Linguistic
Intelligence—
Involves having a mastery of language. This intelligence includes the ability to
effectively manipulate language to express oneself rhetorically or poetically. It
also allows one to use language as a means to remember information.
Spatial
Intelligence—
Gives one the ability to manipulate and create mental images in order to solve
problems. This intelligence is not limited to visual domains--Gardner notes
that spatial intelligence is also formed in blind children.
Materials:
•
15 grams of Hypo (Sodium thiosulfate),
•
test tube
•
test tube rack
•
10 ml graduated cylinder
•
beaker of water
•
burner
•
stirring rod
•
test tube holder
•
balance, funnel
•
paper to hold chemical
•
small spoon
•
goggles
•
apron
SAFETY NOTE: Remind students how to heat a test tube filled with chemical over a flame. Test tube must be pointed
away from students and kept in constant aback and forth motion. Sodium thiosulfate (Hypo) is used in film developing and
students should be careful to wash hands after using this chemical. Due to the solubility of this chemical (15 grams per 2 ml
of water), do not let students pour the hot solution down the drain. It will clog the drain pipes as the solution cools and the
sodium thiosulfate crystallizes. A large beaker in the front of the room should be used. To clean up, students should re-heat
the test tube to dissolve the chemical and pour the hot solution into the large collection beaker. If the budget is tight, the
chemical can be used over again if water is removed and Hypo is allowed to dry out. See Texas Science Safety Manual for lab
and investigation guidelines: http://www.tenet.edu/teks/science/safety/safety_manual.html
Engagement:
Since students are already growing crystals, this lab will answer many questions that they will have:
1. Why do some crystals dissolve when placed into hot solutions?
2. Does it matter what temperature the solution is heated to or how cool the solution should be before the crystal is hung in the beaker?
3. How can I grow the best crystal?
4. Show several crystals and explain that what students learn in this lab will help them become better crystal growers.
Science Course Module: Integrated Physics and Chemistry (IPC) 2005
22
sE
SOLUTION CHEMISTRY
Crystal Clear Science
Explore:
1. Measure 2 ml of water and pour into a clean test tube.
2. Measure out 15 grams of Hypo for use in this lab.
3. Place a few crystals of Hypo into the test tube using the spoon and funnel.
4. Stir. When the crystals have completely dissolved, this is an unsaturated solution.
5. Continue to add hypo and stir. When no more can dissolve, the solution has become saturated. Touch the test tube and
note any temperature changes.
6. Gently heat the solution, adding Hypo until all 15 grams has dissolved. Do not let the solution boil because this will remove
some of the water in the solution.
7. Place the test tube carefully in a beaker of cold water and allow it to cool for at least two minutes. The test tube should be
clear when you remove it from the cold water.
8. At this point the solution is supersaturated. Touch the bottom of the test tube and note the temperature.
9. Drop a few crystals of Hypo into the test tube and shake sideways. Record all observations and include any temperature
changes.
10. Reheat the solution to re-dissolve the Hypo and pour it into a container as directed by your teacher.
Facilitation Questions:
1. What changes did you observe in this lab? Record in your journal.
2. What are the differences between saturated, unsaturated and supersaturated solutions?
Explain:
Answer the following questions in your journal.
1.
What temperature changes did you observe in this experiment? Why did they happen? The solution cooled down as I
added the Hypo but became very warm when the Hypo dropped to the bottom of the test tube. Energy must be
needed to dissolve the Hypo but was released when the Hypo crystallized.
3.
How did the heating of the water affect the solubility of the chemical Hypo? As the water was heated, more and
more Hypo dissolved because the heated water had more energy and dissolved the chemical quickly.
3.
Why was the solution called unsaturated at step 4? The solvent (water) had not dissolved all of the solute (Hypo)
that it could at that temperature. More Hypo could be added and would dissolve.
4.
Why was the solution called saturated at step 5? At that point, the water had dissolved all of the Hypo that it could
at that temperature.
5.
Why was the solution called supersaturated at step 8? At that point, the water had cooled down and should have
“dropped” some of the solute. The solute did not drop to the bottom of the test tube. Since the water is holding more
solute than it should at that temperature, it is supersaturated.
6.
Why did the supersaturated solution begin to drop small crystals when the additional Hypo was added and the test
tube was shaken? I think that the additional solute bumped into the water molecules and the solvent could finally let
go of the extra solute that would not let go until that point.
7.
At what point will the crystallization of the supersaturated solution stop? (When will it stop "snowing"?)
it will stop snowing when the solution is saturated.
8.
In your own words, define the terms: Unsaturated, Saturated, Supersaturated and Solubility. Unsaturated happens
when a solvent has not dissolved all of the solute that it can at that temperature. Saturated happens when the
solvent has dissolved all of the solute that it can at that temperature. Supersaturated happens when the solvent
dissolves all of the solute that it can at a high temperature but cools down. The extra solute that should drop off at
the cooler temperature does not crystallize. The solvent is holding more solute that it usually can hold at that
temperature. Solubility means how much solute dissolves in a certain amount of solvent at a certain
temperature.
I think that
Conclusion: This lab showed the different types of solutions. At the beginning of the lab, the solution was unsaturated
because the water could dissolve more chemical. At step 4 in the lab, the solution was saturated because the water had
dissolved all of the chemical that it could at that temperature. I heated the water and more chemical dissolved. At step 8 in
the lab, the solution was supersaturated because some of the chemical should have dropped out of the solution because the
water cooled and lost the ability to keep the solute dissolved .At step 8 of the lab, the solution became saturated because the
extra chemical dropped out of solution when it started to “snow.” The Hypo dropped out until the water was holding all of the
chemical that it should be holding at that temperature.”
Science Course Module: Integrated Physics and Chemistry (IPC) 2005
23
sE
SOLUTION CHEMISTRY
Crystal Clear Science
Elaborate:
Students can investigate the solubility of other chemicals and find out the amount of solute and solvent needed.
Another important part is to find the temperatures that a student must heat and cool the solutions to grow that
“perfect” crystal.
Evaluate:
Use the following rubric to measure students' understanding of solutions and this investigation.
POINTS
Scientific
Accuracy
4
Procedures were
followed
accurately and
safely.
Excellent
3
Most procedures
were followed
accurately and
safely.
Good
Some procedures
were followed
accurately.
2
Fair
Lab procedures
were not followed
accurately.
1
Poor
Subtotal: ____
Reasoning
Communication
Collaboration
Types of solutions
could be identified
based on their
properties in this
lab. Lab questions
were answered
showing great
understanding of
the properties of
solutions.
Most types of
solutions could be
identified based on
their properties in
this lab. Most lab
questions were
answered showing
much
understanding of
the properties of
solutions.
Some types of
solutions could be
identified correctly
based on their
properties. Some
lab questions were
answered showing
some
understanding of
the properties of
solutions.
Solutions were
incorrectly
identified in this
experiment. Most
lab questions were
incorrectly
answered showing
little understanding
of the properties of
solutions.
Subtotal: ____
Observations were fully
recorded in detail. Lab
questions and
conclusions were well
thought out and
showed a great
understanding of
solutions.
Team worked well
together. Each
member was involved
in the activity and
there was a detailed
discussion of
observations and
conclusions.
Observations were
recorded in detail. Lab
questions were thought
out and showed much
understanding of
solutions.
Team worked fairly
well together. Most
members were
involved in the
activity and there was
discussion of
observations and
conclusions.
Observations were
recorded in some
detail. Lab questions
were answered but
showed some
understanding of
solutions.
Some members of
the team worked
together but with
little discussion of
observations and
conclusions.
Few observations were
recorded but were
without detail. Few lab
questions were
answered and showed
little understanding of
solutions.
The team did not
work together.
Members did not help
each other and did
not discuss the lab
observations and
conclusions.
Subtotal: ____
Subtotal: ____
Science Course Module: Integrated Physics and Chemistry (IPC) 2005
TOTAL:
____/16pts
24
sE
SOLUTION CHEMISTRY
Crystal Clear Science
References/Resources/Websites:
The following sites give information about solutions and crystal growing:
•
http://www.chemistry.co.nz/crystals_defined.htm
•
http:/uk.geocities.com/magoos_universe/crystals.htm
•
http://www.sdnhm.org/kids/minerals/grow-crystal.html
•
http://webphysics.davidson.edu/alumni/MiLee/JLab/crystallography_www/growing.htm
•
http://www.phschool.com/science/science_news/chemistry/properties_matter.html
The following site contains teacher resource lessons:
•
http://visualclutter.com/Links/Science/
The following sites contain information about growing crystals in unusual gravity conditions:
•
http://science.nasa.gov/headlines/y2001/ast11dec_1.htm
•
http://www.mos.org/cst/article/77/3.htm
l
The following sites contain information about many I.P.C. topics including chemistry and crystals:
•
http://www.thinkquest.org/library/cat_show.html?cat_id=36
•
http://www.sciencenews.org/
•
http://www.phschool.com/science/science_news/chemistry/properties_matter.html
Science Course Module: Integrated Physics and Chemistry (IPC) 2005
25
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SOLUTION CHEMISTRY
Crystal Clear Science
IPC: Science Course Module—Goes to the Movies!
University of Houston
The Effect of Temperature on Solubility of KNO3
Type of Lesson:
Content with Process: Focus on constructing knowledge through active learning.
IPC Content TEKS:
9D
Learning Goal/
Instructional Goal:
Demonstrate how various factors influence solubility including
Temperature and nature of the solute and solvent.
In this lab students study the effect of temperature on the solubility of KNO3 .
Instructional Objectives:
•
Given different temperatures students are able to explain the effect of increased
temperature on the solubility of KNO3.
•
Given a solubility curve students are able to determine the solubility of various solutes at
a given temperature.
Key Question:
How does temperature affect the solubility of KNO3?
Related Process TEKS:
(1) Scientific
processes.
The student, for
at least 40% of
instructional
time, conducts
field and
laboratory
investigations
using safe,
environmentally
appropriate, and
ethical practices
The student is expected to:
(A) demonstrate safe practices during field and laboratory investigations; and
(2) Scientific
processes.
The student uses
scientific
methods during
field and
laboratory
investigations.
The student is expected to:
(A) plan and implement experimental procedures including asking questions,
formulating testable hypotheses, and selecting equipment and technology;
(B) make wise choices in the use and conservation of resources and the
disposal or recycling of materials.
(B) collect data and make measurements with precision;
(C) organize, analyze, evaluate, make inferences, and predict trends from
data; and
(D) Communicate valid conclusions.
(3) Scientific
processes.
The student uses
critical thinking
and scientific
problem solving
to make
informed
decisions.
The student is expected to:
(A) analyze, review, and critique scientific explanations, including hypotheses
and theories, as to their strengths and weaknesses using scientific evidence
and information;
(B) draw inferences based on data related to promotional materials for
products and services;
(C) evaluate the impact of research on scientific thought, society, and the
environment;
(D) describe connections between physics and chemistry and future careers;
and
(E) Research and describe the history of physics, chemistry, and contributions
of scientists.
Science Course Module: Integrated Physics and Chemistry (IPC) 2005
26
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SOLUTION CHEMISTRY
To the Teacher:
Crystal Clear Science
For all solids there is a limiting amount that will dissolve in a given amount of solvent. Some
solids are very soluble in water, while others are nearly completely insoluble. About 200
grams of ordinary sugar will dissolve in 100 grams of water at 25°C, but only about 2 x 10-4 g
AgCl will dissolve under those conditions. . Solubility is defined to be the maximum amount of
solute that will dissolve in a given amount of solvent at a specified temperature. The solubility
of a solid in a given solvent depends on the temperature of the solution. Usually the solubility
of a solid increases with increasing temperature, sometimes very noticeably. Typically,
solubilities are recorded as grams of solute per 100g of solvent. For many solutes, increasing
the temperature increases the solubility, that is, more of the solute dissolves in the same
amount of solvent. In this experiment, you will distinguish the temperature behavior of a
solution made up of KNO3 dissolved in water.
A graph which plots the solubility as a function of temperature is called the solubility curve of
the substance. Given such a graph, the solubility of the solid at any temperature may be
determined.
In this lab students study the effect of temperature on solubility. They are given weighed
samples of a soluble salt such as potassium nitrate. The sample is added to 20 ml of water
and heated until all of the salt dissolves. The solution is cooled, and the temperature at which
solid appears is noted. A solubility curve is prepared by pooling the data from all of the
students.
•
•
•
•
The experiment should be done as a class project, with results posted on the board.
Assign samples of KNO3 within a range of 8.00 to 35.00 grams in integral values.
Students tend to report the temperature at which the first tiny crystals are sighted, and
this value is usually low. A more accurate result is obtained by noting the temperature at
which about 5% of the original solid has crystallized.
Solubility curves may be produced in a similar way for other salts. Consult solubility
curves for the ranges which may be assigned. KClO3 and NH4Cl are two salts which are
commonly used in this experiment.
Some students may require assistance in the preparation of the solubility curve. Make
sure that the students are able to interpret the graph, which indicates the increasing
solubility of potassium nitrate with increasing temperature.
Time
Preparation time: 10 minutes
Class Time: 40 minutes
Multiple Intelligences:
LogicalMathematical
Intelligence
Consists of the ability to detect patterns, reason deductively and think
logically. This intelligence is most often associated with scientific and
mathematical thinking.
Materials:
(for 10 students working in pairs)
•
5 400-mL beaker
•
5 25 x 200 mm test tube
•
5 support stand
•
5 heating setup (hot plate; iron ring; wire gauze; burner; striker)
•
5 25-mL graduated cylinder
•
5 single sided buret clamp
•
5 thermometer
•
5 35- to 45-cm length heavy gauge copper wire (for stirrer)
•
100 g KNO3
•
100 mL distilled water
• 1 centigram balance, weighing paper
SAFETY NOTE:
•
•
•
•
•
•
•
These materials may be disposed of in the sink using large amounts of water.
Burns when handling hot objects are possible.
The potassium nitrate and potassium chlorate are strong oxidizing agents.
Handle hot equipment and solutions cautiously and handle the thermometer bulb gently.
Wear goggles and aprons.
Wash hands thoroughly at the end of the experiment.
See Texas Science Safety Manual for lab and investigation guidelines:
http://www.tenet.edu/teks/science/safety/safety_manual.html
Science Course Module: Integrated Physics and Chemistry (IPC) 2005
27
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SOLUTION CHEMISTRY
Engagement:
Crystal Clear Science
Texas Tea Drinker!
Facilitation Questions:
2. As students walk into class sweeten a glass of iced tea with sugar and drink.
3. As the sugar begins to fall to the bottom of the glass ask students to explain what they think is happening.
4. Ask students what could make the sugar dissolve? Write these responses on the board.
Explore:
1.
2.
3.
4.
5.
6.
7.
8.
9.
Set up a 400-mL beaker on an iron ring and wire gauze. Add about 300 mL of tap water.
Weigh out the amount of potassium nitrate, KNO3 , assigned by the instructor. The sample will range from 8.00 to
35.00 grams. Transfer the solid to a large test tube and add 20 mL (20 g) of distilled water.
Stir the mixture with a stirring wire to dissolve as much potassium nitrate as possible. Carefully insert a thermometer.
The glass bulb on the bottom of a thermometer is thin and easily broken.
Heat the water in the beaker with the Bunsen burner. Clamp the test tube in the water.
Use a stirring wire to stir the mixture gently until ALL of the potassium nitrate has dissolved. The temperature may
vary from 25 °C to 85 °C depending on the amount of potassium nitrate in the sample.
When all of the potassium nitrate has dissolved, loosen the clamp from the support stand and raise the tube out of the
water bath. Turn off the burner. Reclamp the tube above and to one side of the beaker. Using the stirring wire, stir the
solution gently and observe it as it cools. As soon as crystallization begins, note the temperature of the solution. It is
easiest to see crystals by looking at the bottom of the test tube where they will collect as soon as they begin to form.
After the crystallization temperature has been recorded, put the test tube back into the water bath and warm the
solution until all of the crystals have redissolved. Repeat the cooling procedure to check the crystallization temperature.
The two readings should be within 1 degree of each other. If the two readings do not agree within 1 degree, rewarm
the solution in the water bath, cool it, and continue until satisfactory agreement is obtained.
Your sample mass will be recorded on the blackboard; record the experimental temperature next to it.
When the data from all of the student samples are recorded at the board, copy them to draw (graph) a solubility curve
for grams of potassium nitrate dissolved per 100 grams of water.
Explain:
1.
Your data furnish the amount of KNO3 that will be dissolved in 20 g of water at each temperature. For each data point,
calculate the amount of KNO3 that would dissolve in 100 g of water. Your calculations will be the solubility of KNO3 in
water at each of the temperatures reported.
Mass of KNO3
8.00
10.0
15.0
20.0
25.0
30.0
35.0
2.
Saturation Temperature °C
26
33
44
57
65
73
83
Mass of KNO3/100g of water
40
50
75
100
125
150
175
Construct the solubility curve for KNO3 . Plot solubility in grams per 100 grams of water on the y-axis and temperature
on the x-axis. Extrapolate the curve to include solubility from 10 °C to 100°C.
Science Course Module: Integrated Physics and Chemistry (IPC) 2005
28
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SOLUTION CHEMISTRY
3.
Crystal Clear Science
Explain how temperature affects the solubility of KNO3. There is a positive correlation between temperature and
solubility of KNO3
Elaborate:
•
•
•
•
Ask students how they would go about testing the solubility of KNO3 in various solvents.
The dissolved oxygen content of water is very critical to marine life. Using the internet investigate the solubility of
oxygen in water as a function of temperature.,
Find solubility graphs of other chemicals
Discuss how crystal growers use solubility graphs to figure out the following:
1. Which solutes will grow the biggest crystals by cooling?
2. How much solute will be needed to grow the crystal?
3. What temperature must the solution be heated and cooled for the best results?
4. Why do certain solutes such as salt grow such small crystals?
Science Course Module: Integrated Physics and Chemistry (IPC) 2005
29
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SOLUTION CHEMISTRY
Crystal Clear Science
Evaluate:
Scientific
Accuracy
POINTS
Reasoning
Communication
Collaboration
I analyzed the data
accurately and
answered analysis
questions
accurately.
I communicated
answers to the
investigation questions
completely and
thoroughly using
correct grammar. I
shared my ideas about
the investigation in the
whole group discussion
and with my
teammates.
I communicated
answers to the
investigation questions
and using correct
grammar. I shared
some of my ideas about
the investigation in the
whole group discussion
and with my
teammates.
I worked very well
with my group. Each
person had a lot of
input and participated
in the investigation.
I analyzed the data
with some errors
and answered
analysis questions
with some errors.
I communicated
answers to the
investigation questions
and with grammatical
errors. I shared a few
of my ideas about the
investigation in the
whole group discussion
and with my
teammates.
I worked somewhat
well with my group.
Each person had
some input and
participated in the
investigation.
I cannot explain
how temperature
affects solubility
of different
solutes. I cannot
create a solubility
curve and read a
solubility curve.
I analyzed the data
incorrectly and
answered analysis
questions
incorrectly.
I communicated
answers to the
investigation questions
and with many
grammatical errors. I
did not share my ideas
about the investigation
in the whole group
discussion and with my
teammates.
I did not work well
with my group. A
few people had input
and participated in
the investigation.
Subtotal: ____
Subtotal: ____
Subtotal: ____
I can accurately
explain how
temperature
affects solubility
of different
solutes. I can
accurately create
a solubility curve
and read a
solubility curve.
4
I can explain how
temperature
affects solubility
of different
solutes. I can
create a solubility
curve and read a
solubility curve.
3
I can sometimes
explain how
temperature
affects solubility
of different
solutes. I can
sometimes create
a solubility curve
and read a
solubility curve.
2
1
I analyzed the data
somewhat
accurately and
answered analysis
questions
somewhat
accurately.
I worked well with my
group. Each person
had input and
participated in the
investigation.
Subtotal: ____
TOTAL:
____/16pts
TAKS-like Items:
1.
A crystal of solute is dropped into a solution and it does not dissolve, but falls to the bottom of
the flask. Identify the type of solution.
A.
B.
C.
D.
Dilute
Saturated
Unsaturated
Supersaturated
Science Course Module: Integrated Physics and Chemistry (IPC) 2005
30
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SOLUTION CHEMISTRY
2.
Crystal Clear Science
Select the statement that lists the various factors that affect the solubility of a solute.
A.
B.
C.
D.
The
The
The
The
solubility
solubility
solubility
solubility
of
of
of
of
a solute increases by heating the solvent, by adding more solute, and by stirring the solute.
a solute increases by cooling the solvent and stirring
the solute increases by adding additional solute and stirring.
the solute increases by stirring the solute, by heating the solvent, and by crushing the solute.
Examine the graph of the solubility curve below to answer question #3.
3.
Based on the graph above, approximately how many grams of KNO3 are dissolved in 20 mL of H2O at 60 °C?
A.
B.
C.
D.
40
30
10
20
g
g
g
g
References/Resources/Websites:
•
•
•
Alternate solubility lab:
http://www.sciencebyjones.com/solubility_of_unknown_salt.htm
Power Point Presentation on solubility
http://personal.tcu.edu/~thanna/1122/lecture13/
Animation dissolving rate of NaCl
http://www.mpcfaculty.net/mark_bishop/NaCl_dissolves.htm
Solubility of KNO3
Solution Chemistry
Science Course Module: Integrated Physics and Chemistry (IPC) 2005
31
sE
SOLUTION CHEMISTRY
Crystal Clear Science
IPC: Science Course Module—Goes to the Movies!
University of Houston
Water as the Universal Solvent
Type of Lesson:
IPC Content TEKS:
Learning Goal/
Instructional Goal:
Key Question:
Related Process TEKS:
1.
Content with Process: Focus on constructing knowledge though active learning.
9A
Relate the structure of water to its function as the universal solvent
Learning goal: Students investigate the properties of water and learn that water's structure allows it to dissolve
many substances and is therefore known as the universal solvent.
Instructional Objectives: Students . . .
1. Predict and prove if water can dissolve eight different substances.
2. Explain why water is called the universal solvent.
3. Identify whether a substance is a solute or a solvent
Will a variety of test substances dissolve in water?
(1) Scientific
processes.
The student, for at
least 40% of
instructional time,
conducts field and
laboratory
investigations using
safe,
environmentally
appropriate, and
ethical practices
(2) Scientific
processes.
The student uses
scientific methods
during field and
laboratory
investigations.
The student is expected to:
(A) demonstrate safe practices during field and laboratory investigations; and
(B) make wise choices in the use and conservation of resources and the
disposal or recycling of materials.
The student is expected to:
(A) plan and implement experimental procedures including asking questions,
formulating testable hypotheses, and selecting equipment and technology;
(B) collect data and make measurements with precision;
(C) organize, analyze, evaluate, make inferences, and predict trends from data; and
(D) communicate valid conclusions.
To the Teacher:
The student is expected to:
(3) Scientific
(A) analyze, review, and critique scientific explanations, including hypotheses and
processes.
theories, as to their strengths and weaknesses using scientific evidence and information;
The student uses
critical thinking and
scientific problem
solving to make
informed decisions.
The structure of a water molecule can help us understand how water can dissolve so many
substances. A water molecule is made up of one atom of oxygen bonded with two atoms of
hydrogen. The atoms are bonded by sharing electrons. This sharing is like an unequal tug of war.
The oxygen atoms attract the electrons more strongly than the hydrogen atoms. The shared
electrons are more attracted to oxygen than to hydrogen. The oxygen "end" of the water molecule
is more negative than the hydrogen "end." The hydrogen end is more positive than the oxygen
Science Course Module: Integrated Physics and Chemistry (IPC) 2005
32
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SOLUTION CHEMISTRY
Crystal Clear Science
end. The oxygen end is said to have a partial negative charge. The hydrogen end is said to have a
partial positive charge.
H
H
O
Multiple Intelligences:
Molecules that have ends with partial negative and positive charges are called polar. Water is a
polar molecule. Water molecules can attract particles of other substances. Many of the substances
that water dissolves are made of polar molecules.
LogicalConsists of the ability to detect patterns, reason deductively and think
Mathematical
logically. This intelligence is most often associated with scientific and
Intelligence—
mathematical thinking.
Linguistic
Intelligence—
Involves having a mastery of language. This intelligence includes the ability to
effectively manipulate language to express oneself rhetorically or poetically. It
also allows one to use language as a means to remember information.
Spatial
Intelligence—
Gives one the ability to manipulate and create mental images in order to solve
problems. This intelligence is not limited to visual domains--Gardner notes
that spatial intelligence is also formed in blind children.
BodilyKinesthetic
Intelligence—
Is the ability to use one's mental abilities to coordinate one's own bodily
movements. This intelligence challenges the popular belief that mental and
physical activities are unrelated.
Materials:
•
•
•
•
•
•
•
•
•
•
•
•
•
Vinegar
Graduated cylinder
8 test tubes per group
test tube rack
sugar
salt
vegetable oil
alcohol
sand
flour
ammonia
soap flakes
cornstarch
SAFETY NOTE:
Goggles and aprons may be worn during the entire lab but especially when ammonia is used.
Students must thoroughly wash hands at the end of the lab. See Texas Science Safety Manual for lab and
investigation guidelines: http://www.tenet.edu/teks/science/safety/safety_manual.html
Engagement:
1.Set up a demonstration with two large beakers of water. Show the students two solutes. Unknown to them, one solute in
soluble in water and one is not. Use sugar or salt as the soluble chemical and perhaps sulfur or Magnesium carbonate as the
insoluble chemical. Drop some of each chemical into the water and observe whether they dissolve. Inquire what dissolving
means to the students and explain how the structure of a solvent affects its ability to dissolve solutes.
2. Show mixtures that have two substances that do not dissolve. Examples might include Italian salad dressing, ocean in a
bottle. Discuss how dissolving is a physical change and how students can recognize if dissolving has taken place.
3. Is water the best solvent to grow your crystal?
Science Course Module: Integrated Physics and Chemistry (IPC) 2005
33
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SOLUTION CHEMISTRY
Crystal Clear Science
Explore:
1.
Copy the data table in your journal and make a prediction if the substances dissolve in water by placing a yes or no in the
prediction column.
2. Place the test tubes in racks. Fill each test with 10 mL of water.
3. Pour 5 mL of alcohol into Tube 1. Gently shake the test tube. Record whether or not it dissolves in water.
4. Place 1 mL of soap flakes in Tube 2. Gently shake the test tube. Record whether or not it dissolves in water.
5. Place 1 mL of sugar in Tube 3. Gently shake the test tube. Record whether or not it dissolves in water.
6. Place 1 mL of flour in Tube 4. Gently shake the test tube. Record whether or not it dissolves in water.
7. Place 1 mL of salt in Tube 5. Gently shake the test tube. Record whether or not it dissolves in water.
8. Place 1 mL of cornstarch in Tube 6. Gently shake the test tube. Record whether or not it dissolves in water.
9. Place 1 mL of sand in Tube 7. Gently shake the test tube. Record whether or not it dissolves in water.
10. Place 5 mL of oil in Tube 8. Gently shake the test tube. Record whether or not it dissolves in water.
Explain:
DATA: Copy in your journal and record your results.
Contents of Test Tube
Prediction if Substance Dissolves in
Water (Yes/No)
Dissolves in Water
(Yes/No)
Alcohol
Soap Flakes
Sugar
Flour
Salt
Cornstarch
Sand
Oil
1.
Did all the substances dissolve in water? No. Why or why not? Not all substances are polar.
2.
Which substances did not dissolve in water? Flour, sand, and oil.
3.
What is a polar molecule? Molecules that have ends with partial negative and positive charges.
4.
What is an ion? An ion is an atom that has lost or gained electrons.
5.
What is a non-polar molecule? A non-polar molecule does not have unequal sharing of electrons. The electron density is
symmetrically distributed among atoms in the molecule.
6.
What is a solvent? The component of a solution that is present in the greatest amount. It is the substance in which the
solute is dissolved. Which substance(s) are considered a solvent? Water.
7.
What is a solute? Solutes are the substances that are dissolved by the solvent. Which substances are considered
solutes? Those substances that dissolved are considered solutes – sugar, salt, alcohol, cornstarch, and soap flakes.
8.
What is hard water and how does it affect solubility? Hard water contains ions, mainly Ca2+, Mg2+ and Fe2+. These ions
increase the ability of water to dissolve polar molecules.
Elaborate:
1. Investigate emulsifiers and apply the research to this lab.
2. Research how to make an ocean in a bottle.
3. Explore other types of mixtures such as dispersions (colloids) and suspensions and compare their properties to that of a solution.
4. Find out information about Carlsbad Caverns and other underground caves that contain stalactites and stalagmites. Explain how they are
formed through the action of water.
5. Conduct an at-home investigation (with family members' assistance) to discover substances at home that do or do not dissolve in water.
Evaluate:
Science Course Module: Integrated Physics and Chemistry (IPC) 2005
34
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SOLUTION CHEMISTRY
Crystal Clear Science
Students answer questions to the lab based on evidence and observations. Use the rubric to evaluate their progress. Awarding a 4
means that the student has done excellent work. Awarding a student a 1 means that the student's
understanding of the subject matter and conclusions need improvement and further practice.
POINTS
Scientific
Accuracy
Lab procedures
were conducted
exactly according
to the directions.
4
3
2
1
Most lab
procedures were
conducted exactly
according to the
directions
Some lab
procedures were
conducted exactly
according to the
directions.
Lab procedures
were not
conducted
according to the
directions
Subtotal: ____
Reasoning
Communication
Collaboration
Predictions were
made for all steps
and lab answers
show great
understanding of
the nature of
solutes and water
as the universal
solvent.
Predictions were
made for most
steps and most lab
answers show an
understanding of
the nature of
solutes and water
as the universal
solvent.
Predictions were
made for some
steps and lab
answers show
some
understanding of
the nature of
solutes and water
as the universal
solvent.
Predictions were
made for few steps
and lab answers
show little
understanding of
the nature of
solutes and water
as the universal
solvent.
Subtotal: ____
Data table was
completely filled out
and all questions were
answered in great
detail showing evidence
of research on the
topic.
Team worked well
together. Members
helped each other
during the
experiment and
discussed the lab
results in great detail.
Data table was mostly
filled out and most
questions were
answered in detail
showing evidence of
research on the topic.
Team worked fairly
well together.
Members usually
helped each other
during the
experiment and
discussed the lab
results in detail
Data table was
somewhat filled out and
some questions were
answered in some
detail showing evidence
of research on the
topic.
Team worked poorly
together. Members
helped each other
rarely during the
experiment and there
was little discussion
of the lab results.
Data table was not
filled out and few
questions were
answered showing little
evidence of research on
the topic.
Team did not work
together at all.
Members did not help
each other during the
experiment and there
was no interaction
between the team
members.
Subtotal: ____
Subtotal: ____
TOTAL:
____/16pts
References/Resources/Websites:
•
•
•
•
•
http://www.chemistry.co.nz/crystals_defined.htm
http://uk.geocities.com/magoos_universe/crystals.htm
http://www.sdnhm.org/kids/minerals/grow-crystal.html (San Diego Natural History Museum)
http://webphysics.davidson.edu/alumni/MiLee/JLab/crystallography_
http://www.phschool.com/science/science_news/chemistry/properties_matter.html
The following site contains teacher resource lessons:
•
http://visualclutter.com/Links/Science
The following sites contain information about growing crystals in unusual gravity conditions:
http://science.nasa.gov/headlines/y2001/ast11dec_1.htm
(crystals in outer space)
•
•
http://www.mos.org/cst/article/77/3.html
(growing crystals in near zero gravity)
Science Course Module: Integrated Physics and Chemistry (IPC) 2005
35
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SOLUTION CHEMISTRY
Crystal Clear Science
The following sites contain information about many I.P.C. topics including chemistry and crystals:
http://www.thinkquest.org/library/cat_show.html?cat_id=36
•
•
•
http://www.sciencenews.org
(This web site has advertisements.)
http://www.phschool.com/science/science_news/chemistry/properties_matter.html
Properties of Matter:
The following sites contain information about chemistry especially matter and crystals:
•
http://www.phschool.com/science/science_news/chemistry/properties_matter.html
•
•
•
•
http://www.chem4kids.com
http://www.school-for-champions.com/science.htm
http://www.thinkquest.org/library/cat_show.html?cat_id=36
http://school.discovery.com/lessonplans/physci.html (teacher lessons)
Science Course Module: Integrated Physics and Chemistry (IPC) 2005
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SOLUTION CHEMISTRY
Crystal Clear Science
IPC: Science Course Module—Goes to the Movies!
1.
2.
3.
4.
What do you think?
What do you think?
5.
6.
Suggested
Teaching
Strategy:
Whole Group
Class Discussion
Draw a graph showing how the mass of the crystal has changed during time
Draw a second graph showing how the size has changed during time.
Make sure that your data table is complete.
Your journal must have the diary entries for each day and sketches of your
crystal.
You must discuss the following questions at the end of your journal entries:
A.
What problems did you have during the project? How did you solve
them?
B.
Why was the water bath in the coffee can needed only on the day
the solution was heated? The water bath slowly cooled down the
solution so that the solute had time to arrange onto the seed
crystals. The slower a crystal grows, the better its shape. If the
water bath had not been used, the seed crystal would have grown
too quickly and the shape would have been poor. After it cooled to
room temperature, the crystal was growing by the evaporation of
the solute.
C.
How did the solubility of your chemical change as the water was
heated and then cooled? As the solvent was heated, its solubility
increased as more solute was dissolved by the solvent. When the
solvent was cooled, its solubility decreased and solute starts to fall
out of the solution.
D.
Under which conditions could your crystal become smaller while in
the beaker of solution? Explain why each would happen and how
you could "fix" each problem. My crystal can become smaller if I
put it into a solution that is too hot and the solvent dissolves the
solute (crystal) because the solution is unsaturated. It can also
dissolve if there is too much solvent and the solution is
unsaturated. In both cases, adding additional solute until the
solution becomes saturated will keep more of the crystal from
dissolving.
E.
Do all chemicals have crystals of the same shape? Suggest reasons
to explain why. Not all crystals have the same shape. In this
project, the Alum crystals look like diamonds while the Copper
sulfate crystals look like parallelograms with slanted sides. The
molecules must fit differently in each solute crystal. It must depend
on the atoms of the different elements that make up each solute
compound and the bonding involved.
F.
How would you improve what you have done in this project to
produce a better crystal?
Teacher facilitates
a class discussion
of findings and
new
understandings
that resulted from
the exploration
activities.
Students do the
explaining.
EXPLAIN
Explain
Write a conclusion by writing your final answer to the problem using what you
have observed in this project.
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SOLUTION CHEMISTRY
Investigate different minerals and what their crystal
shapes are.
Research the names for the different shapes of crystals
and find examples of minerals that have each shape.
Students research
and investigate
everyday energy
issues via a
variety of
extension
activities.
ELABORATE
Elaborate
Crystal Clear Science
Integrate and Elaborate!
Visit a local museum to see the mineral crystal exhibit.
Investigate other crystal growing chemicals besides
Copper II sulfate and Potassium Aluminum sulfate.
Create solubility graphs by using other chemicals
besides KNO3
Use the solubility graphs and analysis questions to allow
students to practice reading graphs.
Perform the Magic Garden Elaboration Activity that is included
Integrate and Elaborate
in this unit.
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Crystal Growing Project RUBRIC
Grading Rubric:
1.
3.
4.
5.
6.
TAKS Items
Use the Rubric
2.
There was a diary entry for each day that students checked their
crystals. ____
Each day, student measured the mass and size of the crystal.
______
There were data tables and graphs. ______
Sketches of the crystal over time were included. ____
The analysis questions (Student lab instructions #13 E 1-6) were
discussed fully. ___
A conclusion was written that showed that the student analyzed
the factors that affect crystal growth and how crystals grow.
____
Student
understanding of
solutions and
crystal growing is
evaluated using a
performance
rubric and by
successfully
responding to a
set of selected
response (TAKSlike) items.
EVALUATE
Evaluate
Science Course Module: Integrated Physics and Chemistry (IPC) 2005
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SOLUTION CHEMISTRY
THUMBS UP!
4
3
2
SCIENTIFIC
ACCURACY of
data and
graphs
All graphs and
data tables are
correctly set up
and completed.
Graphs and data
tables set up
with some
mistakes.
Graphs and data
tables set up
with many
mistakes in data
collection and
plotting graphs.
Crystal Clear Science
REASONING
COMMUNICATION
in written crystal
diary
COLLABORATION
during crystal
growing time
All questions on
crystal growing
are answered
correctly using
observations
Crystal diary was
well organized
with all
requirements met.
All questions
answered clearly
and completely.
Team of students
worked very well
together and shared
all responsibilities
and input.
Most questions
on crystal
growing are
answered
correctly using
observations.
Some questions
on crystal
growing are
answered
correctly using
observation.
Crystal diary was
organized
adequately with
most requirements
met. Most
questions
answered fully.
Team of students
worked together and
shared most
responsibilities and
input.
Crystal diary was
Team worked
somewhat well
together. Each
person had some
responsibilities and
some input.
slightly
disorganized
with some
requirements met.
Some questions
answered.
1
Graphs and data
tables not set up
or set up
incorrectly with
mistakes in data
collection and
plotting graphs.
Questions on
crystal growing
are unanswered
or not based on
valid
observations.
Science Course Module: Integrated Physics and Chemistry (IPC) 2005
Crystal diary was
disorganized with
few requirements
met. Very few
questions
answered and
most of the diary
is unclear and
incomplete.
Team worked poorly
together. The team
did not share
responsibilities or
value the input of
other team
members.
40
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SOLUTION CHEMISTRY
Crystal Clear Science
Solution TAKS Items
Use the information in the table below to answer questions # 1-2
A group of students conducted an experiment to test the dissolving rate of different substances in
water. They obtained 5 grams of four different solutes, four identical glasses, and 50 mL of water
for each solute, which were at room temperature.
Mass of Volume of
Substance
Solute
Water
(g)
(mL)
Washing powder
5
50
Sugar
5
50
Salt
5
50
Baking soda
5
50
1.
According to the data collected, which substance has the fastest dissolving rate?
(TEKS 9D)
A
B
C
D
2.
Time to
Dissolve
(sec)
56
15
18
22
washing powder
sugar
baking soda
salt
Which of the following factors contributed to the dissolving rate of the solute? (TEKS 9E)
A
B
C
D
mass of the solute
volume of the solvent
temperature of the apparatus
chemical composition of the solute
Science Course Module: Integrated Physics and Chemistry (IPC) 2005
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SOLUTION CHEMISTRY
3.
Crystal Clear Science
Two IPC students conducted an experiment to test the solubility of three different substances.
They put 20 mL of three different types of liquids in the same type of
containers and three
different substances. They measured the amount of time it took for the solute to dissolve.
Which of the following procedures will improve their investigation? (TEKS 9E)
A
B
C
D
B
Amount of Solute
Dissolved (g)
Temperature (oC)
C
Temperature (oC)
D
Temperature (oC)
5.
Amount of Solute
Dissolved (g)
A
Amount of Solute
Dissolved (g)
As the temperature of a sample of water increases, the amount of sugar that can be
dissolved in the water also increases. Which graph illustrates this relationship? (TEKS 2C,
2D)
Amount of Solute
Dissolved (g)
4.
stir all three solutions
use the same type of liquid
change the temperatures
use the same solute
Temperature (oC)
A crystal of solute is dropped into a solution but it does not dissolve. Instead it falls to the
bottom of the flask. Identify the type of solution. (TEKS 9D)
A
B
C
D
Dilute
Saturated
Unsaturated
Supersaturated
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Crystal Clear Science
6.
From the information provided on the above solubility graph, how many grams of potassium
nitrate (KNO3) are dissolved in 100g of H2O at 65 degrees Celsius? (TEKS 2C, 2D, 9E)
SOLUTION CHEMISTRY
A
B
C
D
45 grams
50 grams
130 grams
240grams
7. A crystal of solute is dropped into a solution and it does not dissolve, but falls to the bottom of
the flask. Identify the type of solution.
A.
B.
C.
D.
Dilute
Saturated
Unsaturated
Supersaturated
8.Select the statement that lists the various factors that affect the solubility of a solute.
A. The solubility of a solute increases by heating the solvent, by adding more solute, and by
stirring the solute.
B. The solubility of a solute increases by cooling the solvent and stirring
C. The solubility of the solute increases by adding additional solute and stirring.
D. The solubility of the solute increases by stirring the solute, by heating the solvent, and by
crushing the solute.
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9. Examine the graph of the solubility curve below to answer following question:
10. Based on the graph above, how many grams of KNO3 are dissolved in 20 ml of H2O at 60 C?
D.
E.
F.
G.
40g
30g
10g
20g
Unit Materials
1 centigram balance
10 ml graduated cylinder
100 g KNO3
100 mL beakers
250-mL beaker
25-mL graduated cylinder
400 mL beakers
5 35-to 45 cm length heavy gauge wire
5 single buret clamp
50-mL graduated cylinder
Alcohol
Alcohol thermometer
Ammonia
Aprons
Coffee can
Copper Sulfate
Cornstarch
Distilled water
Flour
Funnels
Goggles
Heat resistant gloves
Hot plate
Hot plates
Iron ring
Potassium Aluminum Sulfate
Ring stand
Salt
Sand
Sandpaper
Soap flakes
Sodium thiosulfate
Stirring rods/spoons
Stop watches
Striker
Sugar
Sugar cubes
Test tube rack
Test tubes
Thread
Triple beam balances
Vegetable oil
Vinegar
Water
Weighing paper
Wire gauze
Wooden stirring stick
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Crystal Clear Science
Background Information for Teachers
What should the IPC learner know about Solutions?
The study and design of materials involves several disciplines and issues. An effort should be made
to explore how scientific knowledge fuels technological advances and how technology creates new
scientific knowledge. Chemistry, physics, biology, and geology provide many clear examples of this
interactive relationship between science and technology. As students understand better how atoms
are configured in molecules and crystals (and less-well-defined arrangements), they can begin to see
the connections to large-scale properties of materials. This understanding leads naturally to
laboratory tests that measure a material's physical properties (such as tensile strength, hardness,
and absorbency). Such tests can be included in problems that require students to select and process
materials to give the optimum compromise between properties available and properties needed.
Students should see some automated production process firsthand, if possible, or at least they
should see some media presentations of several automated processes (Benchmarks, 1993).
To develop an understanding of how modern manufacturing works, students need to study and
experience the role of automation in freeing people from tasks that are typically "dull, dirty, or
dangerous." Students should have opportunities to manipulate and program automated devices such
as tabletop robots. Students generally have a lot of misconceptions and negative attitudes about
industrial robots, often based on television and movie depictions of robots. Without concrete
experience, they tend to think robots are intelligent and evil machines that take jobs away from
people. After a little experience playing with an industrial robot, they often report that robots are
very stupid machines that are dependent on people for all the brain work and can perform only the
very simplest tasks (Benchmarks, 1993).
Understanding the general architecture of the atom and the roles played by the main constituents of
the atom in determining the properties of materials now becomes relevant. Having learned earlier
that all the atoms of an element are identical and are different from those of all other elements,
students now come up against the idea that, on the contrary, atoms of the same element can differ
in important ways. This revelation is an opportunity as well as a complication-scientific knowledge
grows by modifications, sometimes radical, of previous theories. Sometimes advances have been
made by neglecting small inconsistencies, and then further advances have been made later by
attending closely to those inconsistencies.
Students may at first take isotopes to be something in addition to atoms or as only the unusual,
unstable nuclides. The most important features of isotopes (with respect to general scientific literacy)
are their nearly identical chemical behavior and their different nuclear stabilities. Insisting on the
rigorous use of isotope and nuclide is probably not worthwhile, and the latter term can be ignored.
The idea of half-life requires that students understand ratios and the multiplication of fractions, and
be somewhat comfortable with probability. Games with manipulative or computer simulations should
help them in getting the idea of how a constant proportional rate of decay is consistent with declining
measures that only gradually approach zero. The mathematics of inferring backwards from
measurements to age is not appropriate for most students. They need only know that such
calculations are possible.
Students should have opportunities-in seminars, projects, readings, and experiments-to reflect on
the value of thinking in terms of systems and to apply the concept in diverse situations. They should
often discuss what properties of a system are the same as the properties of its parts and what
properties arise from interactions of its parts or from the sheer number of parts. They should learn to
see feedback as a standard aspect of systems. The definitions of negative and positive feedback may
be too subtle, but students can understand that feedback may oppose changes that do occur (and
Science Course Module: Integrated Physics and Chemistry (IPC) 2005
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Crystal Clear Science
lead to stability), or may encourage more change (and so drive the system toward one extreme or
another). Eventually, they can see how some delay in feedback can produce cycles in a system's
behavior (Benchmarks, 1993).
Watch out for the following common misconceptions:
Constancy and Change
Lower elementary-school students fail to conserve weight and volume of objects that change shape.
When an object's appearance changes in several dimensions, they focus on only one. They cannot
imagine a reversed or restored condition and focus mostly on the object's present appearance
(Gega, 1986). The ability to conserve develops gradually. Students typically understand conservation
of number between the ages of 6 and 7, of length and amount (solid and liquid) between 7 and 8, of
area between 8 and 10, of weight between 9 and 11, and of displaced volume between 13 and 14.
These ages will vary when different children are tested or the same children are tested in different
contexts (Donaldson, 1978).
Many students cannot discern weight conservation in some tasks until they are 15 years old. The
ability to conserve weight in a task involving transformation from liquid to gas or solid to gas may
rise from 5% in 9-year-old children to about 70% in 14- to 15-year-old-children (Stavy, 1990). More
complex changes, such as chemical reactions, especially those where gas is absorbed or released,
are still more difficult to grasp as instances of weight conservation (Stavy, 1990).
References/Resources/ Helpful websites:
• http://www.chemistry.co.nz/crystals_defined.htm
•
http://uk.geocities.com/magoos_universe/crystals.htm
•
http://www.sdnhm.org/kids/minerals/grow-crystal.html (San Diego Natural History Museum)
http://webphysics.davidson.edu/alumni/MiLee/JLab/crystallography_
•
•
http://www.phschool.com/science/science_news/chemistry/properties_matter.html
The following site contains teacher resource lessons:
•
http://visualclutter.com/Links/Science
The following sites contain information about growing crystals in unusual gravity conditions:
http://science.nasa.gov/headlines/y2001/ast11dec_1.htm
(crystals in outer space)
•
•
http://www.mos.org/cst/article/77/3.html
(growing crystals in near zero gravity)
The following sites contain information about many I.P.C. topics including chemistry and crystals:
http://www.thinkquest.org/library/cat_show.html?cat_id=36
•
•
•
http://www.sciencenews.org
(This web site has advertisements.)
http://www.phschool.com/science/science_news/chemistry/properties_matter.html
Properties of Matter:
The following sites contain information about chemistry especially matter and crystals:
•
http://www.phschool.com/science/science_news/chemistry/properties_matter.html
•
•
•
•
http://www.chem4kids.com
http://www.school-for-champions.com/science.htm
http://www.thinkquest.org/library/cat_show.html?cat_id=36
http://school.discovery.com/lessonplans/physci.html
Science Course Module: Integrated Physics and Chemistry (IPC) 2005
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Crystal Clear Science
PARENTAL PERMISSION SLIP FOR CRYSTAL
(Please consult your science coordinator and principal to make sure this is an appropriate
form to use. You may want to translate your form into any languages that your parents
speak besides English.)
Crystal growing has now come to an end. This unit has been another example of IPC project based
learning approach. Students grew crystals as they investigated solutions, solubility, and chemistry in
other lab activities. For a student to bring his (her) crystal home, you must sign a permission slip
after reading the information below:
Your student has grown one of two crystals:
1. Copper II sulfate (Cupric sulfate) is blue in color. The chemical is used to flush down sewer
and water lines to keep tree roots from growing in the pipes. It tastes like you are chewing on a
piece of aluminum foil and is listed as poisonous on the chemical label. Copper II sulfate is sold in
hardware stores under the name "Blue Stone" if your student wishes to continue to grow his (her)
own crystal at home.
2. Potassium aluminum sulfate (Alum) is white (clear) in color. This chemical has been used as
mouthwash for mouth sores. It is listed as a poison on the chemical's label if swallowed. Alum is sold
in drug stores under the name Ammonium Alum. Ammonium alum has the same crystal shape as
Potassium aluminum sulfate if your student wishes to continue to grow his (her) crystal at home.
3. If you allow your student to take home his (her) crystal, care must be taken that
younger brothers or sisters do not think that the crystal is food and eat it. They must not
drink the solution if the crystal is allowed to continue to grow. Hands must be washed
thoroughly after touching the crystal or solution.
Permission slip:
I ____________________________, parent or guardian of ________________________
(please print name)
(please print name)
have read the information above and allow my student to bring his (her) crystal home from school. I
will discuss safety with the rest of my family and keep the crystal away from younger members of
my family.
Please sign here __________________________________ date _______________
This form must be returned to teacher before the crystal will be sent home.
If this is the last project for the year, I add:
It has been a pleasure to have your student in my class this year. I hope that the experience has
been fun and educational!
_______________________
Mrs. Marintsch
Please feel free to e-mail me at frances.marintsch@springbranchisd.com
or call me at school (713-365-5110) if you have any questions about the crystal or your student's
progress. Thanks!
Science Course Module: Integrated Physics and Chemistry (IPC) 2005
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Crystal Clear Science
STUDENT PAGE
The most familiar solution is a solid dissolved in water. Dissolving a solid in a liquid is an
everyday experience for many people. You make a solution when you make up a powdered
drink mix. When you add lemon powder to water, you make lemonade, a water solution. No
chemical change takes place when a solid is dissolved in a liquid. Does your powder dissolve
faster in tap water out from the sink, water from the refrigerator, or hot water? What are the
factors that affect the rate of dissolving? If the liquid evaporates, the original solid remains
chemically unchanged.
OBJECTIVE: Students demonstrate how factors such as temperature and particle size
influence the rate of dissolving. (TEKS 9D and 9E)
PROBLEM: Which factor is more effective in dissolving sugar, temperature, particle size, or
stirring?
HYPOTHESIS: What do you think? Record your predictions in your science journal.
Safety Precautions:
MATERIALS:
•
•
•
•
•
•
goggles
50-mL graduated cylinder
250-mL beaker
hot plate
alcohol thermometer
heat resistant gloves
• stop watch (2 if possible)
•
•
•
•
•
•
apron
triple beam balance
water
6 sugar cubes
stirring rod/spoon
2 clear cups or 100 mL beakers
PROCEDURES:
1. Safety goggles and laboratory aprons should be worn throughout this experiment.
2. Obtain laboratory materials. READ THE LAB COMPLETELY THROUGH BEFORE
BEGINNING.
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Crystal Clear Science
3. Measure 50 mL of water and place in a 100 mL beaker. Make sure there are no cracks
or chips in the glass before you place the beaker on the hot plate and turn it to high.
Bring to a boil. Continue reading as the water warms. Measure 50 mL of water and
place in a 100 mL beaker of water. This will be your cold water sample.
4. On one paper towel, carefully crush a sugar cube and label it A. Repeat the process for
cube 2 labeling it B. Measure the mass of the sugar cubes separately and record the
results in the appropriate data table in your journal.
5. Once the water reaches the boiling point, use heat resistant gloves to carefully remove
the beaker and set on the table. Do not add the sugar when the water is on the hot plate.
6. Place the crushed sugar sample A in the hot water and time how long it takes for the
sugar to completely dissolve using a stop watch. Do not shake or stir the solution.
Record your observations in your data table in your journal.
HOT
COLD –
COLD –
NOT STIRRED
STIRRED
7. Rinse out all cups and prepare for the next set. Read the data tables for Sets 2 – 4 and
conduct the investigations needed to complete the data tables.
8. Once you are completely finished, WASH each beaker out and dry.
9. Carefully return all materials to materials area, make sure your hot plate is unplugged,
and return goggles and folded apron. Wipe off your work area so it is clean of sugar and
water.
DATA/OBSERVATIONS:
SET
1
COPY THE FOLLOWING DATA TABLES BELOW IN YOUR JOURNAL TO COMPLETE AS YOU WORK.
Cup
Sugar Sample
Water Conditions
A
Crushed
Hot
B
Crushed
Cold
Science Course Module: Integrated Physics and Chemistry (IPC) 2005
Mass (g)
Time (min.)
49
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Sugar Sample
Cube
Cube
Water Conditions
Hot
Cold
Mass (g)
Time (min.)
SET
2
Cup
C
D
Cup
E
F
Sugar Sample
Cube
Cube
Water Conditions
Hot, stirred
Hot, NOT stirred
Mass (g)
Time (min.)
SET
3
Crystal Clear Science
Cup
G
H
Sugar Sample
Crushed
Crushed
Water Conditions
Cold, stirred
Cold, NOT stirred
Mass (g)
Time (min.)
SET
4
SOLUTION CHEMISTRY
ANALYSIS/CONCLUSIONS: (Record in your journal.)
6.
Did you change the same factors in each set?
identifying the independent variable in each set.
Set
Complete the data table below
Independent Variable
1
2
3
4
7.
Were all the dependent variables the same?
identifying the dependent variable for each set.
Set
Complete the data table below
Dependent Variable
1
2
3
4
8.
Complete the data table below identifying the constants for each set.
Set
Constants
1
2
3
4
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9.
How does the particle size affect the rate at which sugar dissolves in water?
10.
How does temperature affect the rate at which sugar dissolves in water?
11.
How does stirring affect the rate at which sugar dissolves in water?
12.
If you wanted to dissolve a substance faster, what should you do?
13.
If you wanted to dissolve a larger amount of substance, say 10 sugar cubes, what should
you do to dissolve the sugar faster?
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STUDENT PAGE
TITLE: Water – The Universal Solvent
OBJECTIVE: Students relate the structure of water to its function as the universal solvent.
(TEKS 9A)
PROBLEM:
H
Will various substances dissolve in water once shaken?
H
O
HYPOTHESIS: What do you know about water? Predict what will happen
when you dissolve (each separately) vinegar, sugar, oil, salt, sand, alcohol, flour, soap,
ammonia, and cornstarch in water?
BACKGROUND INFORMATION:
The structure of a water molecule can help us understand how water can dissolve so many
substances. A water molecule is made up of one atom of oxygen bonded with two atoms of
hydrogen. The atoms are bonded by sharing electrons. This sharing is like an unequal tug of war.
The oxygen atoms attract the electrons more strongly than the hydrogen atoms. The shared
electrons are more attracted to oxygen than to hydrogen. The oxygen "end" of the water molecule is
more negative than the hydrogen "end." The hydrogen end is more positive than the oxygen end.
The oxygen end is said to have a partial negative charge. The hydrogen end is said to have a partial
positive charge. Molecules that have ends with partial negative and positive charges are called
polar. Water is a polar molecule. Water molecules can attract particles of other substances. Many of
the substances that water dissolves are made of polar molecules.
MATERIALS:
Graduated cylinder
test tube rack
flour
vinegar
test tubes
salt
ammonia
sugar
oil
soap flakes
sand
alcohol
cornstarch
PROCEDURES:
1. Copy the data table in your journal and make a prediction if the substances dissolve in water by placing a
yes or no in the prediction column.
2. Place the test tubes in racks. Fill each test with 10 mL of water.
3. Pour 5 mL of alcohol into Tube 1. Gently shake the test tube. Record whether or not it dissolves in water.
4. Place 1 mL of soap flakes in Tube 2. Gently shake the test tube. Record whether or not it dissolves in
water.
5. Place 1 mL of sugar in Tube 3. Gently shake the test tube. Record whether or not it dissolves in water.
6. Place 1 mL of flour in Tube 4. Gently shake the test tube. Record whether or not it dissolves in water.
7. Place 1 mL of salt in Tube 5. Gently shake the test tube. Record whether or not it dissolves in water.
8. Place 1 mL of cornstarch in Tube 6. Gently shake the test tube. Record whether or not it dissolves in water.
9. Place 1 mL of sand in Tube 7. Gently shake the test tube. Record whether or not it dissolves in water.
10. Place 5 mL of oil in Tube 8. Gently shake the test tube. Record whether or not it dissolves in water.
DATA: Draw the chart on the next page in your journal and record your results.
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SOLUTION CHEMISTRY
Contents of Test
Tube
Prediction if Substance
Dissolves in Water
(Yes/No)
Crystal Clear Science
Dissolves in
Water (Yes/No)
Alcohol
Soap Flakes
Sugar
Flour
Salt
Cornstarch
Sand
Oil
CONCLUSIONS/ANALYSIS: Answer the questions in your journal.
1.
2.
3.
4.
5.
6.
7.
8.
Did all the substances dissolve in water? Why or why not?
Which substances did not dissolve in water?
What is a polar molecule?
What is an ion?
What is a nonpolar molecule?
What is a solvent? Which substance(s) are considered a solvent?
What is a solute? Which substances are considered solutes?
What is hard water and how does it affect solubility?
REFLECTION QUESTION: What did you learn about water in this activity? Write about your
new understandings in your science journal.
Science Course Module: Integrated Physics and Chemistry (IPC) 2005
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