Observations and results
Did the Alka-Seltzer tablet dissolve much faster in the hot water compared to the cold? Were there a lot more bubbles produced initially in the hot compared with the cold water?
After the Alka-Seltzer tablet was added to the hot water the tablet should have quickly dissolved, taking some 20 to 30 seconds to do so, depending on the exact temperature. After the tablet was added to the ice-cold water it should have taken much longer to dissolve, with most of the tablet disappearing after about two to three minutes, but with some bubbles still apparent after six minutes or longer. In the hot water the tablet should have more vigorously produced bubbles than in the cold water. The higher the temperature, the faster the molecules move—and the more likely it is that the bicarbonate will contact hydrogen in just the right way for the chemical reaction to occur and produce carbon dioxide bubbles.
More to explore
Chemical Reactions, from Rader's Chem4Kids.com
Factors Affecting the Speed-Rates of Chemical Reactions, from Doc Brown's Science
Rates of Reaction Menu, from Chemguide
Plop, Plop, Fizz Fast: The Effect of Temperature on Reaction Time, from Science Buddies
This activity brought to you in partnership with Science Buddies