Student Experiment 1 - Temperature and Rate of Reaction

1. In order for a chemical reaction to occur, the particles, atoms or ions, which are REACTANTS, must physically come into contact with one another. Anything that increases the frequency of these encounters will increase the rate at which PRODUCTS are formed.

2. The rate of a chemical reaction can be increased by increasing the temperature of these reactants.

My predictions:

Using hot water out of the tap, the rate of reaction will be _________ times faster than at
0 degrees C.

Materials

Note: All experiments should be done using original formula effervescent Alka-Seltzer.

6 Clear cups
Measuring cup
Thermometer, -20 degrees C to 110 degrees C
3 Alka-Seltzer tablets
Stopwatch
Mortar and pestle
Source of hot water
Ice cubes
Graph paper

Procedure

A. Hot Water

1. Run water from the hot tap until it is as hot as possible. Fill a clear glass with exactly 8 oz. of hot water.

2. Use the thermometer to take the temperature and record it on your data sheet.

3. Remove 1 Alka-Seltzer tablet from its package. Drop it into water. measure the time required for tablet to fully dissolve. Be prepared to start and stop on time. The reaction will take less than 15 seconds. Record the time.

B. Room Temperature Water

1. Fill a clear glass with exactly 8 oz. of room temperature or lukewarm water.

2. Use the thermometer to take the temperature and record it on your data sheet.

3. Drop 1 Alka-Seltzer tablet into the water. Measure the time required for the reaction to be completed. Record the time.

C. Cold Water

1. Fill a clear glass with 4 oz. of water and add enough ice to adjust the level to 8 oz. Stir the ice water for about 15 seconds so the temperature will come to equilibrium.

2. Use the thermometer to take the temperature and record it on your data sheet. (Leave the ice cubes in the water!)

3. Drop 1 Alka-Seltzer tablet into the water. Measure the time required for the reaction to be completed. Record the time.

Observations

Water Temperature - Time for Reaction to be Completed

Hot Tap _____ degrees C ______ Seconds

Room temperature ______ degrees C _____ Seconds

Ice Water _____ degrees C _____ Seconds

Analysis

Graph your data points (water temperature vs. time to fully dissolve) to show the effect of temperature on Rate of Reaction.

Summary

As the temperature increases, the rate of reaction _____________________________.

Questions

1. At a temperature of 10 degrees C, it would take ______ seconds for 1 Alka-Seltzer tablet to react with 8 oz. of water.

2. If the temperature is doubled from 20 degrees C to 40 degrees C, the time for the rate of reaction ______by approximately _______.

3. Using hot tap water, the rate was ______ times faster than at 0 degrees C.