Kids, do you think that temperature will have an affect on how fast or slow a reaction might take place? In order for a chemical reaction to occur, the molecules, which are reactants, must physically come into contact with one another. Anything that increases the frequency of these encounters will increases the rate at which products are formed. Your hypothesis can be that the rate of a chemical reaction will be increased by raising the temperature of reactants.
Six clear cups, a measuring cup, a thermometer (-20°C to 110°C), three original formula effervescent Alka-Seltzer® tablets, a stopwatch, a mortar and pestle, a source of hot water, ice cubes, and graph paper.
Fill a clear glass with exactly 50 cm3 of hot water. Use the thermometer to take the temperature and record it on a data sheet. Drop 1 Alka-Seltzer® tablet into water. Measure the time required for the tablet to fully dissolve. Be prepared to start and stop on time. The reaction will take less than 15 seconds. Record the time. Repeat this experiment using room temperature water.
For the cold water test, the procedure is a little different. Fill a clear glass with 25 crn3 of water and add enough ice to adjust the level to 50 cm3. Stir the ice water for about 15 seconds so the temperature will come to equilibrium. Use the thermometer to take the temperature and record it on your data sheet. (Leave the ice cubes in the water!) Drop 1 Alka Seltzer tablet into the water. Measure and record the time required for the reaction to be completed.
Graph your data points (water temperature vs. time to fully dissolve) to show the effect of temperature on rate of reaction.