Name ___________________
Period ______
Endothermic vs. Exothermic Reaction Lab
Background: You have learned that some reactions absorb heat while others
release it. In this lab, you will be experimenting with these two types of reactions.
Materials:
2 Test tubes
thermometer
watch or timer
Calcium chloride
Ammonium chloride
Balance
safety goggles
Graduated cylinder
Procedure: Experiment #1
1. Pour 20 mL of tap water into each of your two test tubes.
2. Take the temperature of both test tubes and record it.
3. Add 6 grams of calcium chloride to one test tube. (don’t do anything to
the other test tube)
4. Take the temperature of the calcium chloride mixture every 20 seconds
for 3 minutes.
5. Now, take the temperature of the other test tube to compare.
Temp:
start 20sec 40sec 1min 1:20 1:40
2:00 2:20 2:40 3:00
CaCl2 + H20
Just H20
Conclusion questions:
1. Did the temperature of the water and calcium chloride go up or down?
By how many degrees?
2. Did the temperature of the plain water go up or down or stay the same?
By how many degrees?
3. Was the water and calcium chloride mixture releasing or absorbing heat?
cold?
4. What affect does that have on how it feels? Will it make it feel hot or
5. What type of reaction was this?
Procedure: Experiment #2
Rinse both your test tubes out well! You will want to start “fresh”
1. Pour 20 mL of tap water into each of your two test tubes.
2. Take the temperature of both test tubes and record it.
3. Add 4 grams of ammonium chloride to one test tube. (don’t do anything to
the other test tube)
4. Take the temperature of the ammonium chloride mixture every 20
seconds for 3 minutes.
5. Now, take the temperature of the other test tube to compare.
Temp:
start 20sec 40sec 1min 1:20 1:40
2:00 2:20 2:40 3:00
NH4Cl + H20
Just H20
Conclusion questions:
1. Did the temperature of the water and ammonium chloride go up or down?
By how many degrees?
2. Did the temperature of the plain water go up or down or stay the same?
By how many degrees?
heat?
cold?
3. Was the water and ammonium chloride mixture releasing or absorbing
4. What affect does that have on how it feels? Will it make it feel hot or
5. What type of reaction was this?
6. Name one common endothermic reaction that you know of:
7. Name one common exothermic reaction that you know of: