Grade: Senior
Subject: Science

#213. Endothermic/Exothermic Lab

Science, level: Senior
Posted by William Murray (wmurray@tminet.com).
Tehachapi Unified School District, Tehachapi, CA
Materials Required: Basic lab materials plus 6M HCl, Zn, NH4Cl and Ba(OH)2 *8H2O
Activity Time: 20 to 30 minutes
Concepts Taught: Endothermic/Exothermic Reactions

Exothermic /Endothermic Lab

Period Names

Procedure I
Obtain a large test tube. Carefully measure 5 ml of 6 M HCl acid into the test tube.
Place a thermometer down into the acid and put the test tube with the thermometer into
the test tube rack. Take the initial temperature reading, record below. Remove the thermometer,
carefully place a piece of zinc (Zn) in the test tube with the acid and replace the thermometer.
Observe the reaction answering the questions below. Watch the thermometer closely and
record the highest temperature obtained (final temperature) during the reaction.
When the reaction is completed, discard the products of the reaction in the beaker back
on the counter and throughly clean the test tube (use the test tube brush) and thermometer.
Initial Temperature C
Final Temperature C
Questions:
1. What type of reaction is this?
2. Was there a gas given off? A smell?
3. Describe the reaction.
4. How much (C) heat flow?

Procedure II
Measure out 3.0 g of Ba(OH)2*8 H2O (remember to use a piece of paper on the balance) and place this
into the dry test tube. Place the dry thermometer down into the compound, take the initial temperature
reading then, remove (clean off any compound that may have stuck onto the thermometer into the tube).
Measure out 1.0 g of NH4Cl and place this into the test tube. Place a #2 stopper over the mouth of the
tube and shake vigorously for 60 seconds. Observe the reaction answering the questions below. Take the
stopper off and place the thermometer down into the test tube and record the lowest temperature obtained
(final temperature) during the reaction. When the reaction is completed, discard the products of the reaction
into the sink with lots of water and throughly clean the test tube (use the test tube brush) and thermometer
Initial Temperature C
Final Temperature C
Questions:
1. What type of reaction is this?
2. Was there a gas given off? A smell?
3. Describe the reaction.
4. How much (C) heat flow?