Background Information

In Lesson 2 you learned about bomb calorimeters and how they are used to measure the energy content of food. Bomb calorimeters are complicated technical devices, and are not available in most high school science laboratories. In this investigation you will construct and determine the precision of a simpler version of a calorimeter.

Purpose

In this investigation you will construct and determine the precision of a calorimeter.

Problem

What is the precision of the calorimeter tested as determined by percent experimental error?

Materials
Photo 1 Procedure

Step 1: Construct a calorimeter by nesting two polystyrene cups.
Photo 2

Step 2: Make a hole in the bottom of the third polystyrene cup. A thermometer will be inserted into this hole later.
Photo 3

Step 3: Use the electronic balance to measure and record the mass of the calorimeter, including the lid.
Photo 4
Photo 5

Step 4: Remove the calorimeter from the balance. Add room temperature water to the calorimeter until it is just less than half full.
Photo 6

Step 5: Use the electronic balance to measure and record the mass of the half-full calorimeter, again, including the lid.
Photo 7

Step 6: Place the lid on the calorimeter and use the thermometer to measure the water temperature in the calorimeter.
Photo 8
Photo 9

Step 7: Use the kettle to prepare warm water with a temperature of approximately 60°C.

Step 8: Add warm water from the kettle to the fourth cup until it is just less than one-third full.
Photo 10

Step 9: Use the electronic balance to measure and record the mass of the fourth cup containing the warm water.
Photo 11

Step 10: Place the lid on the calorimeter and use the thermometer to measure the temperature of the warm water.
Photo 12
Photo 13

Step 11: Transfer the contents of the fourth cup to the calorimeter.
Photo 14

Attach the lid to the calorimeter. Insert the thermometer through the hole made in Step 2, and use the thermometer to gently mix the contents of the calorimeter.
Photo 15

While mixing the contents, observe the temperature change and record the highest temperature for the calorimeter contents.
Photo 16

Step 12: Use the electronic balance to measure and record the mass of the fourth cup.
Photo 17

Step 13: Empty the contents of the calorimeter, dry the inside of the calorimeter, and repeat Steps 4–12 to obtain data for nine more trials.

Step 14: Clean each apparatus used, and return each apparatus to its appropriate place in the laboratory.

Chemistry 30 © 2009 Alberta Education