Chemical Reactions and Temperature Investigation

How does temperature affect the rate of chemical reactions? By speeding up or slowing down the process, of course! "If we change the temperature of the water that the alka-seltzer tablet is introduced to, then it will react faster in cold water." That was my hypothesis. It turns out I was utterly wrong. The fastest time was for the hot water, dissolving completely at 23 seconds.

To go about doing this experiment, you will need the following items. 500 mL beaker, 1 graduated cylinder, 1 thermometer, 3 alka-seltzer tablets, watch or clock, hot plate, ice cubes, water.

For the Hot Water experiment, you will need to first fill your beaker with 266 mL of water. Place the thermometer inside the beaker on the hot plate. Heat it on high until it reaches 50 degrees celsius. Next, use the thermometer to take the temperature and record in you notes. (Be ready with start and stop time!) When the water has reached 50 degrees celsius, remove 1 alka-seltzer tablet from its package and carefully drop it into the water. Measure the time it take to fully dissolve in the water. Record the time.

For the Room Temperature experiment, you will need to first will your beaker with 266 mL of room temperature water. Next, place the thermometer inside the beaker to take the temperature after 1 minute and record. Finally, drop 1 alka-seltzer tablet into the water and record the time.

For the Cold Water experiment, you must first fill your beaker to 133 mL of water. Then add a few ice cubes to get it around the 266 mL mark. Stir the ice water for about 60 seconds so the temperature will even out. Place the thermometer in the beaker and record the temperature. Finally, drop 1 alka-seltzer tablet into the water and record the time.

For my group, the results were:

	Temperature Before	Time	Temperature After
Room	23.9° C	39 s	23.6° C
Hot	50.9° C	23 s	48.6° C
Cold	2.1° C	2 minutes	3.3° C