Overview
Experiment 2Cold Packs Vs. Hand-Warmers
Experiment Inventory
Materials 1/4 Contents of a Cold Pack (ammonium nitrate,
(NH4NO3)
Entire Contents of a Hand Warmer
*Graphing Software
*Computer / Internet Access
*Paper Towels
*Distilled Water
Labware 2 Calorimeters (Styrofoam™ Cups)
10 mL Graduated Cylinder
Scale
Stir Rod
Spatula
Thermometer
Weigh Boat
*Scissors
*Stopwatch / Clock Note: You must provide the materials listed in *red.
EXPERIMENT 2: COLD PACKS VS. HAND-WARMERS In this experiment, you will observe the kinetic energy of molecules by comparing the temperature changes in a calorimeter. Specifically, you will observe the temperature changes for cold packs and hand warmers. Since temperature is defined as the average kinetic energy of the molecules, changes in temperature indicate changes in energy. You will use a Styrofoam™ cup as a calorimeter to capture the energy. The lid will not be placed on the cup since ample oxygen from the air is needed for the hand warmer ingredients to react within a reasonable amount of time.
PROCEDURE
Part 1: Cold Pack
1. Put on your safety glasses and gloves (provided in your safety box).
2. Measure 10 mL of distilled water into a 10 mL graduated cylinder.
3. Turn on the scale by pressing the button labeled “0/T.”
4. Place the weigh boat on the scale and press the 0/T button a second time to zero the scale. Make sure that the units are in grams (g). If not, press the M button until the units displayed are in grams.
5. Using your scissors, cut off the top of your cold pack and weigh out 10 g of the ammonium nitrate (NH4NO3) crystals found in the inner contents of the pack.
6. Place the 10 g of the ammonium nitrate into a Styrofoam® cup. The Styrofoam® cup will be used as a calorimeter.
7. Place a thermometer and a stir rod into the calorimeter (Styrofoam® cup).
8. Pour the 10 mL of distilled water into the calorimeter containing the ammonium nitrate (NH4NO3) taken from the cold pack.
9. Immediately record the temperature and time in Table 4.
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