DAY 6
CHEMISTRY SUMMER SCIENCE INSTITUTE
HOT RODS/COLD CUBES
Locate the thermometer at the front of the lab. Record the temperature of the lab in both
Centigrade and Fahrenheit degrees.
1. Temperature of room ______ oC ______ oF
Find the mass of a metal cylinder on a digital balance. _________g
Place the cylinder into a beaker of room temperature water then heat the beaker on a hot plate
until the temperature of the water is 60o C.
Be careful that the thermometer does not
touch the bottom or sides of the beaker. Remove the cylinder with tweezers; dry it with a
paper towel.
Predict the mass of the cylinder at 60o C. ________g
Why do you think so?
Find the actual mass of the heated cylinder on the digital balance.
Actual mass __________ g
2. Carefully and quickly find the mass of six ice cubes on the digital balance by first finding the
mass of an empty 250mL beaker.
Mass of empty beaker __________g
Mass of beaker and cubes ________g
Mass of cubes ________g
Heat the beaker and cubes gently on a hot plate until approximately half the cubes are
melted. Then re-mass the beaker.
Mass of contents of beaker ________g
What was the effect of adding heat to the mass of the contents of the beaker?
Is heat a form of matter? ________
Why or why not?
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DAY 6
CHEMISTRY SUMMER SCIENCE INSTITUTE
COOL, COOL WATER
On hot summer days, taking a dip in the ocean or a pool is a very inviting idea! Let’s see if we
can figure out why.
1. The temperature of this room is likely to be about 72o F or 22o C. What is the likely
temperature of the water that is sitting out in the beaker?
Why do you think so?
Place your fingers in the water and then remove them. How do your fingers feel?
Is heat moving from the water to your fingers or from your fingers to the water? Why do you
think so?
Wave your hand around. How do your fingers feel now?
What made the difference?
What is happening to the water?
What can you conclude about the relationship between change of state and heat?
Can you explain why standing in front of a fan while you are wet cause chills?
Can you explain why we perspire?
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DAY 6
CHEMISTRY SUMMER SCIENCE INSTITUTE
THINGS ARE HEATING UP
1. Place 10 medium sized ice cubes in a 4150 mL beaker and
add just enough tap water to make the cubes float. Stir the
mixture vigorously with a glass stirring rod and then take
its temperature. It is important that the thermometer not
touch the bottom or sides of the beaker (WHY?) Secure
the thermometer to a ring stand by using a clamp secured
to split rubber stopper that is on the thermometer. Lower
the thermometer into the mixture and continue stirring as
you take the temperature reading.
Initial temperature of water and cubes ________oC.
2. Place the beaker on a hotplate which is on a medium setting and continue stirring (use a
stirring rode). Record the temperature when approximately half the ice has melted.
Temperature when half of the ice is melted ________ oC.
Continue heating and stirring until all of the ice melts. What is the temperature of the water
just as the last of the ice melts?
Temperature of water as last of ice melts ________ oC.
What do you think the heat was doing?
Continue heating and stirring the water for one more minute.
What is the temperature of the water? ________ oC.
What do you think the heat is doing to the water?
Which contains more heat, the ice or the water?
How do you know?
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DAY 6
CHEMISTRY SUMMER SCIENCE INSTITUTE
3. Put the beaker back on the hotplate, continue heating the water and take the temperature
every 30 seconds until the water boils.
Reading Time
oC
Reading Time
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oC
DAY 6
CHEMISTRY SUMMER SCIENCE INSTITUTE
________ oC
Take the temperature of the boiling water
Continue boiling the water for one minute. Take the temperature of the boiling water.
________ oC.
What was the effect of the heat on the water from the time the ice melted until boiling
started?
What was the effect of the heat on the water once boiling started?
Make as many observations as you can as the water is boiling.
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DAY 6
CHEMISTRY SUMMER SCIENCE INSTITUTE
HOT AND COLD – BIG AND SMALL
At this station, you will find two thermometers held by rubber stoppers and clamped to ring
stands. You will also have an empty small beaker and an empty large beaker on the table and a
hot plate.
Fill each beaker about half-way with water from the tap. Place each beaker on the hot plate and
lower the thermometers into the water. Make sure the thermometers are not touching the sides or
bottoms of the beakers. Read the initial temperature of each sample of water in Centigrade
degrees.
Small beaker ________ oC
Big beaker ________ oC
Heat the water by turning on the hot plate to a medium-high setting. Heat each beaker
simultaneously until the temperature reaches 60oC in one beaker.
What is now the same about the two beakers?
What is different about getting these beakers?
Continue heating until the second beaker is at 60oC.
What can you say about the amount of heat in the big beaker as compared to the amount of heat
in the small beaker? Explain.
If two objects are at the same temperature does that mean that they contain the same amount of
heat? Explain
If you were blindfolded and placed only a finger into each of the beakers, could you distinguish
the large and small beakers? ______________ If so, how?
Is temperature a measure of the amount of heat of an object?
What does temperature measure?
Are there any questions you would like to ask?
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DAY 6
CHEMISTRY SUMMER SCIENCE INSTITUTE
ENERGETIC CHEMICALS
1. Caution – goggles must be worn! Place one Styrofoam cup into another. Use a graduated
cylinder to measure 50mL of a 1M NaOH solution. Pour this solution (sodium
hydroxide/lye) into the cup. Place a cardboard cover over the cup. Insert a thermometer
through the center of the cardboard cover into the solution.
Temperature of the NaOH solution ________o C.
Measure 55mL of a 1M HC1 (hydrochloric acid) solution using the graduated cylinder and
add the acid into the cup. Stir the chemicals with the thermometer, and take the temperature
once a minute for the next 3 minutes.
After 1 minute ________o C.
After 2 minutes ________o C.
After 3 minutes ________o C.
What observation can you make?
What conclusion can you make?
Why do you think it was necessary to perform this experiment in the doubled-up Styrofoam
cups instead of using a glass beaker?
2. In this activity, you will perform the same chemical reaction twice. The reaction is between
iron (Fe) and copper Sulfate (CuSO4). CuSO4 is a solid, but the blue liquid on the lab table is
a solution of CuSO4, or CuSO4 dissolved in water.
In the first try at this reaction, you will put the two chemicals directly in contact with one
another.
Place about 1 inch of CuSO4 solution in a small beaker, then add the iron nail. Wait about 1
minute, and remove the nail with plastic tweezers and place it on a paper towel.
Describe what you see on the nail.
Where must this material have come from?
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DAY 6
CHEMISTRY SUMMER SCIENCE INSTITUTE
The chemical equation for what occurred is:
Fe + CuSO4 → Cu + FeSO4
Now do you know the identity of the coating on the nail? _______________________
If you continuously scraped the coating off, more and more of it would reform until all of the
blue color was removed from the solution or all, the nail was gone. Where would the iron be
when the reaction was over?
This reaction is an example of REDOX – or oxidation and reduction. The Fe, which is an
uncharged element, forms the compound FeSO4 in which the iron has a charge of +2.
Fe → Fe+2
Two electrons, 2e- , left the iron and this resulted in the +2 charge. The loss of e-’s is oxidation.
Feo - 2e → Fe+2
In CuSO4, the Cu has a charge of +2, but when it became free elemental copper it has no charge.
Cu+2 → Cuo
Two electrons were added to the Cu+2 and this resulted in neutral Cuo . A gain of electrons is
called reduction.
Cu+2 + 2e → Cuo
So in this redox reaction, electrons were exchanged; 2 were lost from the Fe (oxidation) and 2
were gained by Cu+2 (reduction).
You will now perform this reaction again, but this time you will physically separate the
chemicals and connect them to wires through which electrons can travel.
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DAY 6
CHEMISTRY SUMMER SCIENCE INSTITUTE
3. See the following diagram which
illustrates the set-up. Attach a wire to a
clean Cu strip using an alligator clip
and suspend the nail into a solution of
CuSO4 in an unglazed porcelain cup.
Attached a second wire to a nail and
suspend the nail into a solution of
FeSO4 in a large beaker. Connect the
free ends of the wires to a DC voltmeter
and watch what happens!
In which direction along the wire do you think electrons are flowing? Why
What is the name commonly given to a flow of electrons through a wire?
Using this set up how could you get a small light bulb to light?
Assuming that the filament in the bulb would not burn out, when would the bulb go out?
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DAY 6
CHEMISTRY SUMMER SCIENCE INSTITUTE
BAGGING IT
1.
Locate the sealed plastic bag on the desk. Make as many observations you can about the
contents using sight and feel WITHOUT OPENING THE BAG. Record these in the
table below. Be sure to include the states of matter.
2.
Place the bag on a balance and record the mass.
3.
Remove the bag from the balance. WITH THE BAG SEALED, carefully pop the top off
the small vial of liquid and shake the bag so that all the materials are well mixed.
4.
With the bag still sealed, record what you see and feel in the table below.
5.
Place the bag back on the balance and record the mass again. ______________________
_______________________
DATA
BEFORE MIXING
AFTER MIXING
What do you think?.....
1.
What were the big changes that you noticed?
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DAY 6
CHEMISTRY SUMMER SCIENCE INSTITUTE
2.
Do you think this was a chemical or physical change? Why did you conclude that?
2.
What happened with the mass? Did you expect this? Why or why not?
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DAY 6
CHEMISTRY SUMMER SCIENCE INSTITUTE
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