DAY 5
CHEMISTRY SUMMER SCIENCE INSTITUTE
SOLIDS, LIQUIDS, GASES I – SOME PROPERTIES
1. Discuss the properties in the table that you know for solids, liquids, and gases with your
partners and fill in the blanks with the appropriate word or phrase.
SOLIDS
LIQUIDS
SHAPE
(Definite or
Indefinite?)
VOLUME
(Definite or
Indefinite?)
POURABILITY
(Yes or No)
GASES
*see #2
2. To help you answer the pour ability question about gases, you can easily make some carbon
dioxide and see if you can pour it. Place two full spatulas of sodium bicarbonate in a beaker.
Add about ½ inch of vinegar. Cover the beaker with a glass plate. Light a candle and place it
on the lab table. Lift the covered beaker over the lit candle, remove the glass plate and
carefully “pour” only the CO2 onto the candle. Record your observations.
3. Give the name associated with the following changes in state and give a common example of
each kind of change.
NAME
EXAMPLE
SOLID TO LIQUID
LIQUID TO GAS
SOLID GAS
GAS TO SOLID
LIQUID TO SOLID
GAS TO LIQUID
4. Can all material things exist in any of the three states of matter? Explain your answer.
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DAY 5
CHEMISTRY SUMMER SCIENCE INSTITUTE
SOLIDS, LIQUIDS, GASES II - COMPRESSIBILITY
In this activity, you will squeeze each of the three states of matter to see how they behave. We
can learn about the tiniest bits of matter, even though we can’t see atoms and molecules, from
how large amounts of matter behave.
Before you begin, do you think it’s possible to compress each of the three states of matter?
Please talk it over with your partners and put your prediction and the reason(s) you think so in
the space provided below.
SOLIDS
LIQUIDS
GASES
1. Take a large syringe, remove the plunger, and fill it halfway with the solid provided. Replace
the plunger, point the tip upward and gently push the plunger to expel the air. Place a piece
of tape over the tip and tap down on the solid to make sure it is firmly packed. Rest the open
end of the syringe on a cork to prevent the solid from running out. Once again gently push
on the plunger. What happened to the volume (space occupied) by the solid as pressure was
applied?
___________________________________________________________________
2. Remove all solid from the syringe. You may have to clean out the syringe a bit by using a
twisted paper towel. Push the plunger all the way down and place the tip of the syringe into a
beaker of water. Pull up on the plunger until the syringe is ½ filled with water. Get rid of
any air bubbles by pointing the tip upward and pushing the plunger. Place the tip of the
syringe on the cork and push gently on the plunger. If water squirts out then you are pushing
too hard. What happened to the volume of the water as pressure was applied?
____________________________________________________________________
Were you able to compress the liquid?
__
3. Empty the water. Now your syringe is filled only with air. Press the plunger down the
halfway point then stopper it by placing the tip against a cork on the table. Gently push
down on the plunger. What happened to the volume of air as pressure was applied?
____________________________________________________________________
Were you able to compress the gas?
_
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DAY 5
CHEMISTRY SUMMER SCIENCE INSTITUTE
Although we cannot see atoms (even with a microscope), based on what you just did, what can
you theorize (make an explanation) about some differences in the spaces between particles
(atoms and molecules) of solids, liquids, and gases.
What do you think is in the space between particles?
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DAY 5
CHEMISTRY SUMMER SCIENCE INSTITUTE
BREAKING INTO SOLIDS, LIQUIDS, GASES
1. Dry an ice cube with a paper towel and place it on a watch glass. Gently place one drop of
food coloring on the ice cube and wait about a minute. Carefully pick up the cube with tongs
and wipe it with a paper towel. What do you observe about the color?
__________________________________________________________________
Draw a picture of what you see.
2. Fill a 250 mL clean beaker with tap water. Let it sit on the lab table undisturbed for one
minute. Gently place two drops of food coloring on the surface of the water.
What do you see immediately?
What do you see after 1 minute?
What do you see after 3 minutes?
In the space below draw three pictures representing the beaker at the three time intervals.
IMMEDIATELY
1 MINUTE
3 MINUTES
What can you theorize about the differences between the particles of solids and liquids
based on what you saw?
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DAY 5
CHEMISTRY SUMMER SCIENCE INSTITUTE
3. Have the members of your group space themselves in a line about nine feet long. You can all
go out in the hallway for this activity. Try to find a place where there are not a lot of drafts
or people walking by. Have the first person in line hold a bottle of solid air freshener and
open the top.. Time how long it takes for each person in the line to smell the air freshener.
Everyone should stay as still as possible while this is taking place.
SECONDS
PERSON #1
PERSON #2
PERSON #3
What must be true about particles of gas based on your observations?
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DAY 5
CHEMISTRY SUMMER SCIENCE INSTITUTE
SKIMMING THE SURFACE
Water, water everywhere – and it’s such an interesting liquid!
1. Take a small test tube and fill it to the very top with tap water.
How many drops of water do you think you can add before the water will spill over?
Using an eyedropper continue to add water drop by drop, counting as you go, until the water
spills.
Number of drops needed
Describe what you saw as you were adding the drops of water.
2. Clean a penny with soap and water and place it on the lab table. How many drops of water
do you think you can place on the penny before the water will spill onto the table?
Your predicted number of drops
The actual number of drops
3. Fill a small beaker with water. Very carefully lay a headless pin or aluminum paper clip
sideways on the surface of the water. It might help to use tweezers to place the pin.
Observations
Place the needle point first into the water.
Observations
From the above three activities, what seems to be true about the surface of the water?
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DAY 5
CHEMISTRY SUMMER SCIENCE INSTITUTE
4. Which will evaporate more easily a beaker of hot water or a beaker of cold water?
Why do you think this is so?
What does “evaporation mean?
How is evaporation different from “boiling?”
5. Place a few drops of water on the lab table and a few drops on a piece of waxed paper.
Describe what you see?
Do you think water molecules are more attracted to each other or to wax molecules?
Explain your choice.
Do you think that water molecules are more attracted to each other or to the molecules of the
table? Explain.
Are there any questions you would like to ask?
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DAY 5
CHEMISTRY SUMMER SCIENCE INSTITUTE
DISCOVERING THE SHAPE OF CRYSTALLINE SUBSTANCES
View the various available household substances under a microscope or magnifying glass.
Describe or illustrate the shape of the crystals.
Substance
Epsom salt – magnesium sulfate
Description or Illustration
Table salt – sodium chloride
Table sugar - sucrose
Milk sugar - lactose
Note: Some common household chemicals such as baking soda, baking powder, and alum are
powdered substances and the crystals are too small to see with a low powered microscope.
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DAY 5
CHEMISTRY SUMMER SCIENCE INSTITUTE
ALUMINUM CAN PLAYTIME
A
B
C
1. If figure A represents an open aluminum can sitting on the lab table, and Pi is the pressure of
the air inside the can, and Po is the pressure outside the can, then do you think:
Pi = Po
or
Pi > Po
or
Pi < Po?
Explain the choice.
In figure B, the can is being crushed. Which condition do you think exists?
Pi = Po
or
Pi > Po
or
Pi < Po?
Explain the choice.
In figure C, the can is exploding. Which condition do you think exists?
P1 = PO or
P1 > P O
or P1 < PO
Explain the choice.
2. a. Place a small amount (about 5 mL) of water into an aluminum can.
b.
Place the can on a hot plate, set on high, and heat until the water is boiling and
steam is clearly escaping. Let it boil for about 1 minute, but do not allow it to go
to dryness.
c.
Using tongs, quickly invert the can into icy cold water.
d.
Describe what happened.
e.
Which of the following condition occured?
Pi > Po
f.
or
Pi < Po?
Can you think of a possible explanation for the result?
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DAY 5
CHEMISTRY SUMMER SCIENCE INSTITUTE
WHAT WOULD HAPPEN IF THERE WAS NO AIR?
The world we live in is filled with air. Air is a mixture of gases. We are not always aware that
the air is there because we cannot see it. But, we can feel the air when the wind blows.
The apparatus at this station is a vacuum pump. It will suck the air out of the heavy glass
chamber called the bell jar. You are going to place some items into the bell jar and see what
happens to them when the air is taken away.
Vacuum pump and bell jar
Bell jar
1. Blow up a little balloon so it about the size of your closed fist and tie it off with a knot.
Take a marshmallow out of the bag.
Shake up the can of shaving cream and squirt a small amount into a 100 mL beaker.
2. Now carefully slide the bell jar off the metal platform of the vacuum pump. The contact
point of the bell jar and the platform should be coated with grease to insure a good seal.
Place the balloon, marshmallows, and shaving cream on the platform. Place the bell jar over
these items. In the space below draw a little picture of the items in the bell jar. Now turn the
switch and suck the air out of the bell jar. Wait about two minutes then draw another picture
of the items that you put into the bell jar.
10
DAY 5
CHEMISTRY SUMMER SCIENCE INSTITUTE
WITH AIR
WITHOUT AIR
What happened to the balloon, marshmallows, and shaving cream when the air was removed
from the bell jar?
What does this result tell you about air?
11
DAY 5
CHEMISTRY SUMMER SCIENCE INSTITUTE
HOW ARE THE PRESSURE AND VOLUME OF A GAS RELATED?
(MIDDLE SCHOOL ACTIVITY)
1.
Let’s explore this relationship between pressure and volume quantitatively. Locate the
station with the CB, TI-83 calculator, and pressure sensor. Be sure that the syringe
plunger is pulled out a little past 20 mL (cc) and the blue valve is in line with the clear
plastic side opening.
Select [PRGM] on the TI-83. When the
program are displayed select CHEMBIO and
[ENTER]. Press [ENTER] twice until you
reach the MAIN MENU. Select SET-UP
PROBES and enter the following information:
Number of probes: 1
Select probe:
3: PRESSURE
Channel number:
1
Calibration:
USE STORED
Pressure units:
ATM
When you get back to the MAIN MENU select
2: COLLECT DATA. For DATA
COLLECTION select 3: TRIGGER
/PROMPT.
Pick up the syringe and push the plunger to 20 mL (cc). When you have the volume set,
press the TRIGGER button on the CBL. When you get the ENTER VALUE message
on the calculator enter the syringe volume. The menu will ask if you want to enter more
data, stop and graph, or quit. Select MORE DATA and repeat the procedure above with
a volume that is 4 mL less. Collect data for 3 more volumes that are decreased by 4 mL
each.
After the 5th value, select STOP & GRAPH.
The calculator should display a graph. If it
does not, check with the instructor. Sketch
the graph below labeling the axes with the
appropriate variable name (x = volume, y =
pressure)
What mathematical relationship do you think
exists between volume and pressure?
Explain.
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DAY 5
CHEMISTRY SUMMER SCIENCE INSTITUTE
Write a possible mathematical expression for pressure and volume based on your data.
What would you estimate the pressure to be for a volume of 30 mL on the syringe? __________
Before going on, exit the CHEMBIO Program by selecting NO when asked if you want to repeat
the experiment. Select QUIT when you return to the MAIN MENU.
To test if your prediction is correct we can use the power of the TI-83. The data you collected
with the CBL is in lists. Key in [STAT] and then [ENTER]. L1 is volume, L2 is pressure.
Transfer the data from the calculator to the table below. Calculate the product of volume and
pressure (V x P) for each data pair and enter it in the table. Calculate the average k value.
VOLUME (V)
PRESSURE (P)
k (=VxP)
Average k
To determine the equation that best describes the
relationship between pressure and volume on the
TI-83, go to STAT PLOTS ( [2nd] [Y =] ). Turn
off all plots but number 1 and set up to plot L1
versus L2. Display the graph by hitting [ZOOM]
[9] and sketch it here, labeling the axes.
13
DAY 5
CHEMISTRY SUMMER SCIENCE INSTITUTE
Determine what type of relationship exists between P and V (that is, linear, power, quadratic).
Go to [STAT] CALC and select the regression equation. When the screen shows the regression,
key in L1, L2 and press [ENTER]. Record the screen information below. If your screen does
not show r and r2 values, ask your instructor to show you how to display these.
Equation form: ________________________________________
a = __________________________
r2 = _________________________
b = __________________________
Fill in the values and place the equation here:
___________________________
How does the average value of k compare to the coefficient “a” in the regression equation?
Now, write the equation in terms of the variables P and V not x and y:
___________________________________________________________
To see how the data fits the regression equation go to [ Y =] and clear all functions. Press
[VARS], arrow down to 5:STATISTICS and [ENTER]. Arrow over to EQ and select RegEQ.
This will “paste” the regression equation into the Y = function. Hit [GRAPH] and the data
points will appear and the regression equation will be plotted with the points.
Using the regression equation, calculate the pressure for a volume of 30 mL. How good was
your prediction?
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