Unit 2
Chemistry
Unit 2- Chemistry: Matter/Periodic
Table/Acids & Bases
LESSON OUTLINE:
I.
II.
III.
IV.
Matter
a. Phases of Matter
b. Conservation of Matter
c. Physical and Chemical
Change
d. Phase Change and Energy
e. Gas Laws
Elements and the Periodic Table
a. Atomic Models
b. Periodic Table Organization
c. Metals vs. Nonmetals
Atoms and Bonding
a. Chemical Symbols
b. Chemical Formula Writing
c. Chemical Bonding
Chemical Reactions
a. Balancing Equations
b. Acids and Bases
c. Neutralization of an Acid
KEY CONCEPTS:
As students progress through the year
learning about the biotic and abiotic
environment, the movement of
chemicals in pathways, like Nitrogen
and Sulfur in acid rain production, and
cycles such as the carbon cycle,
becomes very important. This unit is
designed to give the students the
“chemical language skills” needed to
understand these pathways and cycles.
OUTCOMES:
Upon completion of this lesson,
students will be able to:
1. describe how matter is conserved
even though it may change
properties as it forms compounds or
changes physically.
2. explain how the periodic table is
organized based on the atomic
model and how the characteristics
of different elements are related to
the number of electrons on the outer
shell of the element’s atoms.
3. write proper chemical formulas
based on the atoms valence
electrons in the compound.
4. describe the properties of acids and
bases and describe with a chemical
equation how an acid and a base
can combine to make a salt and
water.
GRADUATION STANDARDS:
The following MN graduation
standards apply:
8.2.1.1.1 Distinguish between a mixture and a
pure substance and use physical properties to
separate mixtures and identify pure substances.
8.2.1.1.2 Use physical properties to distinguish
between metals and non-metals.
8.2.1.2.1 Identify evidence of chemical
changes, including color change, generation of
a gas, solid formation and temperature change.
8.2.1.2.2 Distinguish between chemical and
physical changes in matter.
8.2.1.2.3 Use the particle model of matter to
explain how mass is conserved during physical
and chemical changes in a closed system.
8.2.1.2.4 Recognize that acids are compounds
whose properties include a sour taste,
characteristic color changes with litmus and
other acid/base indicators, and the
tendency to react with bases to produce a salt
and water.
9.2.1.2.1 Describe the role of valence
electrons in the formation of chemical bonds.
9.2.1.2.2 Explain how the rearrangement of
atoms in a chemical reaction illustrates the law
of conservation of mass.
9.2.1.2.3 Describe a chemical reaction using
words and symbolic equations.
Unit 2- Chemistry: Matter/Periodic
Table/Acids & Bases
LEARNING ACTIVITIES:
I.
Assign reading: (6 hours) Chapter 1 sections 1-3 and Chapter 2
sections 1-3: from the Prentice Hall Science Explorer ©2009 Chemical
Building Blocks and have students do reading previews, answer key
concept questions, define key terms and do the Target Reading Skills.
II.
Phases of Matter: (1 hour) “What Changes Do You See”
Introduce matter with a simple observation exercise of the different phases
of matter.
a. Materials
i. Beaker
ii. Watch plate
iii. Ice cubes
iv. Food coloring
v. Hot water
b. Procedure: Have the students follow the following procedure with ice,
water, beaker.
i. Fill a beaker 1/3 full of HOT water.
ii. Put one drop of food coloring in the hot water
iii. Place an ice cube in the hot water.
iv. Cover the beaker with the watch glass.
v. Place an ice cube on top of the watch glass.
c. Have students answer the following questions as they observe the
apparatus.
i. What state of matter is the water? __________________ (Solid,
Liquid, Gas)
ii. What state of matter are the ice cubes? __________________
(Solid, Liquid, Gas)
iii. What changes in the state of matter is occurring to the ice cube in
the water?
iv. What changes in the state of matter is occurring at the surface of
the water?
v. What changes in the state of matter is occurring on the bottom of
the watch glass?
vi. Why is the water on the bottom of the watch glass not colored?
d. Conclusion:
i. What determines the state of matter?
ii. Review experiment questions at the end of the hour.
Unit 2- Chemistry: Matter/Periodic
Table/Acids & Bases
III.
Conservation of Matter: (1 hour) “What is Matter” Introduce the
law of conservation of matter with the following exercise. Have the students
describe the law by doing the following experiment.
a. Notes: - Matter is anything that has mass and occupies space.
b. Ask the Question: What happens to the mass of water when you add
sugar?
c. Materials:
i. Water
ii. Sugar
iii. Triple-beam Balance
d. Have students determine if the mass changes when combining sugar and
water.
i. Measure 100 ml of water
ii. Find the mass of the water (don’t include the mass of the
graduated cylinder)
iii. Measure 10 g of sugar
iv. Mix sugar and water
v. Measure the final mass of water and sugar mixture
e. Post lab questions: Ask students to answer the following questions.
i. What was the starting mass of the water?
ii. What was the mass of the sugar?
iii. What happened to the mass of the water after you added sugar?
iv. How close was the mass of the
sugar plus the mass of the water
to the mass of the combined
sugar and water mass?
Mass of sugar + Mass of
water = Mass of combined water
and sugar
f. Conclude the last 15 minutes of the
class period by having the students
answer the question “A glass of
unsweetened lemonade weighs 255
grams. A spoonful of sugar weighs 25
grams. Predict how much you think the
sweetened lemonade will weigh after
you stir in the sugar.” From the
“Uncovering Student Ideas in Science:
25 formative assessment probes” Keeley, Page. Uncovering Student
Ideas in Science. Arlington, VA: NSTA, 2005. Print.
Unit 2- Chemistry: Matter/Periodic
Table/Acids & Bases
IV.
V.
Physical and Chemical Change Card Activity: (1 hour) Have the
students use the cards in this activity to introduce examples of physical and
chemical changes and have the students build a working definition of
“physical” and “chemical” change. At the end of the class period, to fill out
an exit ticket, “Define a chemical change.” And “Define a physical change.”
Collect the exit tickets as the students leave the classroom. Use it as a tool
to measure the growth in understanding from today’s lesson.
Physical and Chemical Stations Lab: (1 hour) At the start of the
hour review student responses to exit ticket. Then have students move
between 7 stations (3 minutes per sation) to decide if the change happening
at the station is a physical or chemical change based on the definition given
in class at the start of the hour, and have them explain their reasoning.
a. Materials
i. Matches
ii. Test tubes
iii. Salt water bath
iv. Vinegar
v. Baking soda
vi. Seltzer tablet
vii. Ice
viii. Potato
ix. Iodine Solution
x. Salt
b. Procedure: Set up and have the students cycle through the following
seven stations:
i. Station 1 - Matches – chemical change – gas
production, light, heat
Strike a match and watch it as it burns. Blow the match out before
it burns your fingers. When your observations are completed,
rinse the used match in tap water and dispose of it in the watch
glass on lab table.
ii. Station 2 -Water Baths - physical change – phase
change
Fill a test tube ¼ or less with tap water. Place it in the salt-water
ice bath and stir it around gently and constantly for 2-3 minutes
(possibly more) without removing it. Take the test tube out.
Record your observations. Rinse the inside AND outside of the
test tube well with water and return to the test tube rack.
Unit 2- Chemistry: Matter/Periodic
Table/Acids & Bases
VI.
iii. Station 3 – Vinegar and baking soda – chemical – gas
production
Put about 1 cm of vinegar into a test tube. Then use a stick to put
a SMALL (about ½ cm long on the stick) amount of baking soda
into the tube. After your observations are complete, pour the test
tube contents into the sink, and rinse the test tube with water
before putting it back into the rack.
iv. Station 4 - Seltzer Tablet – chemical change gas
production
Fill a test tube about ¼ full with tap water. Put a small piece of
crushed seltzer tablet into the water in the test tube. When you
have completed your observations, pour the test tube contents
into the sink, and rinse the test tube with water before putting it
back into the rack.
v. Station 5 - Ice – physical change – phase change
Put 2 or 3 small pieces of ice into a test tube and observe what
happens as the solid ice turns to a liquid. When you have
completed your observations, pour the test tube contents into the
sink and rinse it before returning it back to the rack.
vi. Station 6 Iodine on a Potato – chemical change – color
change
Cut a SMALL fresh slice from the potato. Use a dropper to put 34 drops of iodine solution on the potato slice. After your
observations are complete, throw away the used slice of potato
into the trashcan
vii. Station 7 Salt – physical change – dissolving of a solid
Fill a test tube about ¼ full with tap water. Use a spoon handle to
add 1/2 cm (long on the stick) of salt to the water. Shake the test
tube gently until the salt dissolves. When you have completed
your observations, pour the test tube contents into the sink, and
rinse the test tube with water before putting it back into the rack.
c. Conclusion: Based on the previous exercise, and today’s activity, ask if
anything was created or destroyed, or were things changed from one
form to another. Just because things changed, was there anything that
stayed the same? Return the students answers the “lemonade probe”
and discuss if the lab stations
Chemistry in a Bag: (2 hours) This activity has students build on
previous day’s activities, have students perform the following 3 lab
exercises to observe chemical reactions and to observe changes in pH.
Show an image of the pH scale and show, which side is acid and which is
Unit 2- Chemistry: Matter/Periodic
Table/Acids & Bases
base, and explain how an indicator can help us determine this.
(www.middleschoolscience.com/bag.htm)
a. Materials
i. Baking soda
ii. Phenolphthalein (or cabbage juice)
iii. Test tube
iv. Clear ziplock bags
v. Calcium chloride
b. Procedures: Have the students do the following three experiments:
i. Procedure Bag 1:
1. Place 2 tsp of baking soda into the bag.
2. Add 30 mL of Phenolphthalein to the bag. (Skip this step
if you are using cabbage juice)
3. •Massage the bag to mix the contents.
4. VERY CAREFULLY - lower the test tube containing 30 mL
of water upright into the bag. (OR Lower a small cup or
beaker with 50 ml of cabbage juice as a substitute). Do
not let any spill out.
5. Have the student hold the test tube gently from the outside
of the bag while squeezing the excess air out and seal the
bag.
6. Hold the test tube and bag up and slowly spill the water
out of the test tube (while the bag is still sealed). The
contents will turn bright pink. Cabbage juice will turn
greenish blue for a base and purple-ish for neutral, pink for
acid.
7. As the students look at and feel the contents of the bag
they will see the baking powder dissolving and the contents
turning pinker.
ii. Procedure Bag 2:
1. Place 2 tsp of calcium chloride into the bag.
2. Add 30 mL of Phenolphthalein to the bag. (Skip this step
if you are using cabbage juice)
3. Massage the bag to mix the contents.
4. VERY CAREFULLY - lower the test tube containing 30 mL
of water upright into the bag. (OR Lower a small cup or
beaker with 50 ml of cabbage juice as a substitute) Do not
let any spill out.
5. Have the student hold the test tube gently from the outside
of the bag while squeezing the excess air out and seal the
Unit 2- Chemistry: Matter/Periodic
Table/Acids & Bases
bag.
6. Hold the test tube and bag up and slowly spill the water
out of the test tube (while the bag is still sealed). The
contents will turn bright pink and start to get warm.
cabbage juice will turn greenish blue for a base and
purple-ish for neutral, pink for acid.
7. As the students look at and feel the contents of the
bag. They will see the calcium chloride dissolving and the
contents turning pinker and getting warmer.
iii. Procedure Bag 3:
1. Place 2 tsp of baking soda into the bag.
2. Place 2 tsp of calcium chloride.
3. Add 30 mL of Phenolphthalein. (Skip this step if you are
using cabbage juice)
4. Massage the bag to mix the contents.
5. VERY CAREFULLY - lower the test tube containing 30 mL
of water upright into the bag. (OR Lower a small cup or
beaker with 50 ml of cabbage Juice as a substitute) Do
not let any spill out.
6. Have the student hold the test tube gently from the outside
of the bag while they squeeze the excess air out and seal
the bag.
7. Hold the test tube and bag up and slowly spill the water
out of the test tube (while the bag is still sealed). The
contents will turn bright pink. Cabbage juice will turn
greenish blue for a base and purple-ish for neutral, pink for
acid
8. Have the students write down observations. At this point,
they will see the baking powder and calcium chloride
dissolving, foaming, bubbling, instead of pink, it will
become clear/white, and the bag will be warm. The bag
will start to inflate and puff out.
c. Conclusions: Students should write a conclusion as to why each bag
did reacted the way it did. Students should be able to identify each
chemical and physical change that happened and what caused each of
them.
VII.
Boil ice water: (2 hour) with temperature probes to graph the
temperature change over time as energy is added to the system. This lab
allows students to see how energy is needed to change the phase.
Unit 2- Chemistry: Matter/Periodic
Table/Acids & Bases
a. Materials
i. Beaker
ii. Ice
iii. Probeware/Thermometer
iv. Hot plate
b. Procedure
i. Fill the beaker halfway with ice. Do not place the beaker on the
hot plate yet. Observe the beaker of ice for 3-4 minutes. Draw a
picture and record any changes in your notes.
ii. Place the probeware or regular thermometer in the beaker so it is
between the ice cubes. If you are using a regular thermometer,
have the students make a data table in their notebook and record
the beginning temperature on the data table at 0 min. If you are
using the probeware, press "start." The program will record and
graph the time temperature for the entire lab. Do not press stop
until the water has reached a boiling point and has boiled for
three minutes.
iii. Place the beaker of ice on the hot plate and turn the dial to 7. If
you are using a regular thermometer, use a stopwatch and record
the temperature every minute in the data table. Continue to
collect data until the water has begun to boil and has boiled for
three minutes. If you are using the probeware, remember to
continue to collect the data until the water has reached a boil and
has boiled for three minutes. DO NOT PRESS "STOP."
iv. After the water has boiled for three minutes, turn off the hot
plate. Leave the beaker on the hot plate and allow it to cool. If
you are using the regular thermometer, record your final reading.
c. Conclusions: If the students are doing the data with a regular
thermometer, have them graph their data. If they used the probeware
have them use their graph and ask the students to compare their graph
with the following images and go through these questions as a class.
Unit 2- Chemistry: Matter/Periodic
Table/Acids & Bases
VIII. “It’s a Gas” Lab (1 hour) (Prentice Hall Science Explorer ©2009 Chemical
Building Blocks) Have the students demonstrate the gas laws by applying
pressure to and observing the air in a syringe.
a. Materials
i. Syringe
ii. Clay
iii. Books
b. Procedure
i. Make a data table in your notebook.
ii. Lift the plunger of the syringe as high as it will move without going
off scale. The volume inside the syringe will then be as large as
possible.
iii. Seal the small opening of the syringe with a piece of clay. The
seal must be airtight.
iv. Hold the syringe upright with the clay end on the table. With the
help of a partner, place one book on top of the plunger. Steady
the book carefully so it does not fall.
v. With the book positioned on the plunger, read the volume shown
by the plunger and record it in your data table.
vi. Predict what will happen as more books are placed on top of the
plunger.
vii. Place another book on top of the first book resting on the plunger.
Read the new volume and record it in your data table.
viii. One by one, place each of the remaining books on top of the
plunger. After you add each book, record the volume of the
Unit 2- Chemistry: Matter/Periodic
Table/Acids & Bases
syringe in your data table.
ix. Predict what will happen as books are removed from the plunger
one by one.
x. Remove the books one at a time. Record the volume of the
syringe in your data table after you remove each book.
c. Analyze and Conclude:
i. Graphing Make a line graph of the data obtained from Steps 5,
7, and 8. Show volume in cubic centimeters (cm3) on the vertical
axis and number of books on the horizontal axis. Title this
Graph 1.
ii. Graphing Make a second line graph of the data obtained from
Step 10. Title this Graph 2.
iii. Predicting Did the results you obtained support your predictions
in Steps 6 and 9? Explain.
iv. Interpreting Data Compare Graph 2 with Graph 1. How can
you explain any differences in the two graphs?
v. Drawing Conclusions What does Graph 1 tell you about how
the volume of a gas changes with increasing pressure?
a. Communicating Write a paragraph explaining how the volume of the
gas changed as books were added one by one. Base your explanation
on what was happening to the gas particles in the syringe.
IX. Assign reading: (5 hours) Chapter 3 sections 1- 5 from the Prentice Hall
Science Explorer ©2009 Chemical Building Blocks and have students do reading
previews, answer key concept questions, define key terms and do the Target
Reading Skills.
X. Reading jigsaw on the different atomic models, Dalton, Rutherford,
Thompson, Bohr model: (1 hour)
a. Have the students in 4 groups, assign each group a model to read about
and have the students answer their assigned questions found on the
following document.
b. After the group has read and answered the questions, have them use the
large portable white boards to draw the model, and put important
characteristics of their atomic model and explain it to the rest of the class.
As each group presents, to the rest of the class.
XI. Periodic Table Basics Activity: (5 hours) After learning about the different
atomic models, now the students can look at differences seen in the different
elements known.
Unit 2- Chemistry: Matter/Periodic
Table/Acids & Bases
a. Complete the squares for each element by adding the atomic number,
name, and atomic mass.
b. Determine the number of protons, neutrons, and electrons in each
element.
c. Create a Bohr diagram for each element.
d. Draw the Lewis Structure for each element.
e. Use the assigned colors to shade in the square for each element. You
should ONLY color in the small square in the upper left-hand corner and
not the entire card.
f. Cut the cards apart and arrange according to atomic number in the
pattern shown below. Once you have the cards arranged in the correct
order, glue them to a large sheet of construction paper.
XII.
“Copper or Carbon – That is the Question” Lab: (1 hour) Prentice Hall
Science Explorer ©2009 Chemical Building Blocks Have the students
perform the following observations. Materials scientists work to find the best
materials for different products. In this lab, students will look for an answer
to the following problem: How do the properties of copper and graphite
determine their uses? You will compare the properties of a copper wire and
a pencil lead. Pencil lead is made mostly of graphite, a form of the
nonmetal element carbon.
a. Materials
i. 250 mL beaker
ii. Hot plate
iii. Copper sample
iv. Graphite sample
v. Light bulb
vi. Socket
vii. Battery cell
b. Procedure:
i. Fill a 250-mL beaker about three-fourths full with water. Heat it
slowly on a hot plate. Let the water continue to heat as you
complete Part 1 and Part 2 of the investigation.
ii. Part I - Physical Properties –
1. Compare the shininess and color of your copper and
graphite samples. Record your observations.
2. Bend the copper wire as far as possible. Next, bend one
of the graphite samples as far as possible. Record the
results of each test.
iii. Part II - Electrical Conductivity
Unit 2- Chemistry: Matter/Periodic
Table/Acids & Bases
1. Place a bulb into a lamp socket. Use a piece of insulated
wire to connect one pole of a dry cell battery to the socket.
2. Attach the end of a second piece of insulated wire to the
other pole of the dry cell battery. Leave the other end of
this wire free.
3. Attach the end of a third piece of insulated wire to the
other pole of the lamp socket. Leave the other end of this
wire free.
4. Touch the free ends of the insulated wire to the ends of the
copper wire. Record your observations of the bulb.
5. Repeat Step 7 using a graphite sample instead of the
copper wire.
iv. Part III – Heat Conductivity
1. Turn off the hot plate.
2. Hold one end of a graphite sample between the fingertips
of one hand. CAUTION: Be careful not to touch the
beaker.
3. Dip both the graphite and copper wire into the hot water at
the same time. Allow only about 1 cm of each piece to
reach under the water’s surface. From your fingertips to the
water, the lengths of both the graphite sample and the
copper wire should be approximately equal.
4. Time how long it takes to feel the heat in the fingertips of
each hand. Record your observations.
c. Analyze and conclude using the following questions:
i. Observing Compare the physical properties of copper and
graphite that you observed.
ii. Classifying: Based on the observations you made in this lab,
explain why copper is classified as a metal.
iii. Controlling Variables: In Step 11, why was it important to use
equal lengths of copper wire and graphite?
iv. Drawing Conclusions: Which of the two materials, graphite or
copper, would work better to cover the handle of a frying pan?
Explain your choice.
v. Communicating: Write a paragraph explaining why copper is
better than graphite for electrical wiring. Include supporting
evidence from your observations in this lab.
XIII. Alien Periodic Table Activity: (4 hours) Prentice Hall Science
Explorer ©2009 Chemical Building Blocks Have the students imagine that
Unit 2- Chemistry: Matter/Periodic
Table/Acids & Bases
inhabitants of another planet send a message to Earth that contains
information about 30 elements. However, the message contains different
names and symbols for these elements than those used on Earth.
a. Have the students figure out which elements on the periodic table do
these “alien” names represent?
i. The element doggone (D) has only 4 protons in its atoms.
ii. Floxxit (Fx) is important in the chemistry of life. It forms
compounds made of long chains of atoms. Rhaatrap (R) and
Doadeer (Do) are metals in the fourth period, but rhaatrap is less
reactive than Doadeer.
iii. Magnificon (M), goldy (G), and sississ are all members of Group
15.
iv. Goldy has fewer total electrons than magnificon.
v. Urrp (Up), oz (Oz), and nuutye (Nu) all gain 2 electrons when
they react. Nuutye is found as a diatomic molecule and has the
same properties as a gas found in Earth’s atmosphere. Oz has a
lower atomic number than urrp.
vi. The element anatom (An) has atoms with a total of 49 electrons.
vii. Zapper (Z) and pie (Pi) lose two electrons when they react.
Zapper is used to make lightweight alloys.
b. Analyze and conclude using the following questions.
i. Drawing Conclusions: List the Earth names for the 30 alien
elements in order of atomic number.
ii. Classifying: Were you able to place some elements within the
periodic table with just a single clue? Explain using examples.
iii. Interpreting Data: Why did you need two or more clues to place
other elements? Explain using examples.
iv. Inferring: Why could you use clues about atomic mass to place
elements, even though the table is now based on atomic
numbers?
c. Communicating: Write a paragraph describing which groups of elements
are not included in the alien periodic table. Explain whether or not you
think it is likely that an alien planet would lack these elements.
XIV. Bonding Basics: (2 hours) Identify the number of valance electrons in a
given atom, describe and demonstrate how an ionic bond forms, and
describe and demonstrate how a covalent bond forms. Predict the type of
bond that will occur between two elements.
a. Write the symbols for each element.
b. Use Skittles (or other cereal/candy with more than one color) to create
Unit 2- Chemistry: Matter/Periodic
Table/Acids & Bases
c.
d.
e.
f.
XV.
the Lewis structure for each.
Draw an arrow (or more if needed) to show the transfer of electrons
and move the cereal to the new location.
Determine the charge for each ion and write the formula.
Make sure the sum of the oxidation numbers is zero and write the
chemical formula.
Have the students use a pencil or crayon to draw the electrons as they
remove the pieces of cereal.
Chemical Formula Writing: (3 hours)
Using the knowledge that atoms bond the way they do because of their
valence electrons, scientists can predict which atoms will combine together
and make compounds that can be represented in chemical formulas. In their
notebooks, have the students take notes, Chemical Nomenclature Notes formula writing.pdf. Then write the names or the formulas on the Chemical
Formula Writing Assignment also found on the classroom website.
XVI. Conductivity Lab Vernier: (2 hour) As students have used
understanding of atomic structure to understand how atoms combine to
make molecules or compounds, these compounds have different properties.
In this experiment, students will study the electrical conductivity of water and
various water solutions. A solution can contain molecules, ions, or both.
Some substances, such as sucrose (C12H22O11), dissolve to give a solution
containing mostly molecules. An equation representing the dissolving of
sucrose (table sugar) in water is
C12H22O11(s) ⎯⎯ → C12H22O11(aq)
Other substances, such as calcium chloride (CaCl2), dissolve in water to
produce a solution containing mostly ions. An equation is
CaCl2(s) ⎯⎯ → Ca2+(aq) + 2 Cl-(aq)
Have students use a Conductivity Probe to test the electrical conductivity of
solutions, and determine which, molecules or ions, are responsible for electrical
conductivity of the following solutions:
sodium bromide, NaBr, solution
potassium chloride, KCl, solution
calcium chloride CaCl2, solution
aluminum chloride, AlCl3, solution
ethanol, C2H6O, solution
ethylene glycol, C2H6O2, solution
2-propanol, C3H8O, solution
Unit 2- Chemistry: Matter/Periodic
Table/Acids & Bases
sucrose, C12H22O11, solution
distilled water
tap water
a. Materials
i. Conductivity probe and computer interface
ii. sodium bromide, NaBr, solution
iii. potassium chloride, KCl, solution
iv. calcium chloride CaCl2, solution
v. aluminum chloride, AlCl3, solution
vi. ethanol, C2H6O, solution
vii. ethylene glycol, C2H6O2, solution
viii. 2-propanol, C3H8O, solution
ix. sucrose, C12H22O11, solution
x. distilled water
xi. tap water
b. Procedure
i. Obtain and wear goggles.
ii. Connect the Conductivity Probe to the computer interface. It should
be set on the 0–20000 µS/cm position. Conductivity is measured in
microsiemens per centimeter (µS/cm).
iii. Prepare the computer for data collection by opening the file “16
Conducting Solutions” from the Physical Science with Vernier folder.
iv. Measure the conductivity for each of the solutions. CAUTION: Many
of these solutions are poisonous. Avoid inhaling any vapors from the
solutions. Avoid contacting them with your skin or clothing. Be careful
not to contaminate the solutions.
v. Raise the beaker until the hole in the probe end is completely
submerged in the solution as shown in Figure 1. Swirl the solution
briefly.
vi. Once the reading has stabilized, record the conductivity value.
vii. Before testing the next solution, clean the probe by surrounding it
with a 250 mL beaker and rinsing it with distilled water from a wash
bottle. Carefully blot the probe dry with a tissue.
c. Analyze and conclude with the following questions:
i. Consider solutions 2–9. Which solutions conduct electricity best—
those containing mostly ions or those containing mostly molecules?
ii. Does distilled water conduct electricity well? Explain.
iii. Does tap water conduct electricity? Account for this observation.
iv. Consider the conductivity readings for the KCl, CaCl2, and AlCl3
solutions. What trend do you observe? Account for this trend.
Unit 2- Chemistry: Matter/Periodic
Table/Acids & Bases
v. Suggest three other substances whose water solutions would conduct
electricity well. Explain how you made your choices.
d. EXTENSION
i. Test your predictions for Question 5 above.
XVII. Balancing Chemical Equations: (2 hours)
Students have built understanding of atomic bonding, and understand that the
law of conservation of mass applies to matter. Now when ionic compounds
form, the ions come together the students will balance out the charges on the
ions. The chemical formula for the compound reflects this balance. Have the
students work on the Balancing Chemical Equations worksheet.
XIII. pH Lab: (3 hours) During this activity students will recognize that acids are
compounds whose properties include a sour taste, and characteristic color
changes with litmus. And bases are compounds whose texture tends to be
slippery, and have characteristic color changes with litmus.
a. Materials
i. Beakers
ii. Mr. Clean liquid
iii. Grapefruit Juice
iv. Milk
v. Vinegar
vi. Soap water
vii. Baking soda in water
viii. Lemon juice
b. Procedure: Students move between 7 stations to measure pH of the different
liquids using pH paper, record the reaction of the blue and red litmus paper to
the liquid, and depending on the liquid, describe the smell, feel and/or taste
of the liquid. Students record this information on a post-it note for each liquid
and at the end of visiting all 7 of the stations the students put the post-it notes
on a large pH scale out in the hallway. Students look for similarities between
the post-it notes on the scale of 1 to 14.
i. Stations include: Mr. Clean liquid, grapefruit juice, milk, vinegar, soapy
water, baking soda in water, lemon juice.
c. Wrap-up: After the students have looked for patterns on the hallway pH scale,
ask the following questions:
i. What did you notice for substances that had a pH of less than 7? (sour
taste)
ii. What about substances that had pH of more than 7? (slippery texture)
Unit 2- Chemistry: Matter/Periodic
Table/Acids & Bases
iii. What could you say about an unknown substance’s pH if it felt slippery?
(above 7)
XIX. Neutralization of an Acid Lab: (2 hours)
In a culminating activity, have the students mix equal amounts of an acid (.1M HCl)
and a similar molar base (.1M NaOH) with an indicator that changes at 7
(phenolphthalein), and the tendency to react with bases to produce a salt and water.
a. Use the procedure from Long Beach High School.
b. Analyze and Conclude: In the last 15 minutes of the class period, ask
the students the following questions (exit ticket if you have time):
i. On average how much of the base was needed to change the 10 mL
of acid to a neutral solution (where the phenolphthalein indicator
changed color pH of 7)?
ii. What are the products of mixing an acid with a base?
iii. Finish the equation HCl + KOH à ???
XX. Antacid Test: (2 hours) Prentice Hall Science Explorer ©2009 Chemical
Building Blocks The students at this point have the understanding of how
chemicals behave and how they can be observed. The students will focus on
the following skills; designing experiments, interpreting data, and measuring.
Which antacid neutralizes stomach acid with the smallest number of drops?
a. Materials
i. Hydrochloric acid
ii. Plastic dropper
iii. Different antacid
iv. Methyl orange solution
b. Procedure:
i. Part 1
1. Using a plastic dropper, put 10 drops of hydrochloric acid
(HCl) into one cup. CAUTION HCl is corrosive. Rinse spills
and splashes immediately with water.
2. Use another plastic dropper to put 10 drops of liquid
antacid into another cup.
3. In your notebook, make a data table to record the colors of
the HCl and the antacid.
4. Add 2 drops of methyl orange solution to each cup. Record
the colors you see.
5. Test each of the other antacids. Discard all the solutions and
cups as directed by your teacher.
ii. Part 2
Unit 2- Chemistry: Matter/Periodic
Table/Acids & Bases
1. Methyl orange changes color at a pH of about 4. Predict the
color of the solution you expect to see when an antacid is
added to a mixture of methyl orange and HCl.
2. Design a procedure for testing the reaction of each antacid
with HCl. Decide how many drops of acid and methyl
orange you need to use each time.
3. Devise a plan for adding the antacid so that you can detect
when a change occurs. Decide how much antacid to add
each time and how to mix the solutions to be sure the
indicator is giving accurate results.
4. Make a second data table to record your observations.
5. Carry out your procedure and record your results.
6. Discard the solutions and cups as directed by your teacher.
Rinse the plastic droppers thoroughly.
c. Analyze and Conclude:
i. Designing Experiments: What is the function of the methyl
orange solution?
ii. Interpreting Data: Do your observations support your
predictions from Step 6? Explain why or why not.
iii. Inferring: Why do you think antacids reduce stomach acid?
Explain your answer, using the observations you made.
iv. Controlling Variables: Explain why it is important to use the
same number of drops of HCl in each trial.
v. Measuring: Which antacid neutralized the HCl with the smallest
number of drops? Give a possible explanation for the difference.
vi. Calculating: If you have the same volume (number of drops) of
each antacid, which one can neutralize the most acid?
vii. Drawing Conclusions: Did your procedure give results from
which you could draw conclusions about which brand of antacid
was most effective? Explain why or why not.
d. Design an Experiment: (if time permits)
A company that sells a liquid antacid claims that its product works faster
than tablets to neutralize stomach acid. Design an experiment to compare
how quickly liquid antacids and chewable antacid tablets neutralize
hydrochloric acid. Obtain your teacher’s permission before carrying out
your investigation.
Unit 2- Chemistry: Matter/Periodic
Table/Acids & Bases
RESOURCES:
Prentice Hall Science Explorer 2009
“Chemical Building Blocks”
Lemonade worksheet
https://primaryproficient.wikispaces.co
m/file/view/Lemonade.pdf
E2 Class website
https://murray.spps.org/e2_environme
ntal_inquiry_immersion_2.html
Physical and Chemical Change Lab
http://www.slcschools.org/department
s/curriculum/science/Grade-7-to8/Grade-8/documents/Physical-andChemical-Changes.pdf
Famous Scientist Worksheet
http://www.learnnc.org/lp/multimedia
/11342
Periodic Table Basics
http://www.sciencespot.net/Media/pta
blebasics.pdf
Chemical Bonding Basics
http://sciencespot.net/Media/bonding
basics2010.pdf
Balancing Chemical Equations
Worksheet
http://www.kentchemistry.com/
Worksheets/Regents/Units/Math
ofChem/WSBalancing21.pdf
Acid Base Titration Lab
www.kentchemistry.com/Labs/Lab%20
Titration.doc
EQUIPMENT:
Phases of Matter
• Beaker
• Watch plate
• Ice cubes
• Food coloring
• Hot water
Conservation of Matter
• Water
• Sugar
• Triple-beam Balance
Physical and Chemical Stations
• Matches
• Test tubes
• Salt water bath
• Vinegar
• Baking soda
• Seltzer tablet
• Ice
• Potato
• Iodine Solution
• Salt
Chemistry in a Bag
• Baking soda
• Phenolphthalein (or cabbage juice)
• Test tube
• Clear ziplock bags
• Calcium chloride
Boil Ice Water
• Beaker
• Ice
• Probeware/Thermometer
• Hot plate
It’s a Gas Lab
• Syringe
• Clay
• Books
Copper or Carbon
• 250 mL beaker
• Hot plate
• Copper sample
• Graphite sample
• Light bulb
• Socket
• Battery cell
Conductivity Lab
Unit 2- Chemistry: Matter/Periodic
Table/Acids & Bases
Conductivity probe and computer
interface
• sodium bromide, NaBr, solution
• potassium chloride, KCl, solution
• calcium chloride CaCl2, solution
• aluminum chloride, AlCl3, solution
• ethanol, C2H6O, solution
• ethylene glycol, C2H6O2, solution
• 2-propanol, C3H8O, solution
• sucrose, C12H22O11, solution
• distilled water
• tap water
pH Lab
• Beakers
• Mr. Clean liquid
• Grapefruit Juice
• Milk
• Vinegar
• Soap water
• Baking soda in water
• Lemon juice
Antacid Test
• Hydrochloric acid
• Plastic dropper
• Different antacid
• Methyl orange solution
•
GLOSSARY:
Matter - Anything that has mass and
occupies space.
Chemistry - The study of the
properties of matter and how matter
changes.
Physical property - A characteristic
of a substance that can be observed
without changing the substance into
another substance.
Chemical property - A characteristic
of a substance that describes its ability
to change into different substances.
Element - A substance that cannot be
broken down into any other substances
by chemical or physical means.
Atom - The smallest particle of an
element.
Chemical bond - The force that holds
atoms together.
Molecule - A neutral particle made of
two or more atoms joined by covalent
bonds.
Compound - A substance made of
two or more elements chemically
combined in a specific ratio, or
proportion.
Chemical formula - A combination of
symbols that represents the elements in
a compound.
Physical change - A change that
alters the form or appearance of a
material but does not make the
material into another substance.
Chemical change - The process in
which substances undergo chemical
changes that result in the formation of
new substances.
Law of conservation of mass - The
principle stating that matter is not
created or destroyed during a chemical
reaction.