Chemical Reactions and Temperature Lab Investigation

Today we decided to find out if temperature would affect the reaction time of of alka-seltzer and water. My question is: What happens to a chemical when you add or take away heat? My hypothesis is: If we heat up a chemical reaction, then it will speed up the reaction. Here is my data:
Room Temperature Water: Used 266mL of water, started at 23.9ºC and ended at 23.6ºC while taking 39 seconds for the reaction to occur.
Cold water: Used 133mL of water, started at 2.1ºC and ended at 3.2ºC while taking 2 minutes for the reaction to occur.
Hot water: Used 266mL of water, started at 50ºC and ended at 48.6ºC while taking 23 seconds for the reaction to occur.

A Graph of the reaction times and the temperatures

I accepted my hypothesis because by making the reaction hotter, it sped up the reaction.