Animation of an experiment showing the effect of surface area of the reactants on the rate of a chemical reaction. On each of the digital scales is a conical flask containing hydrochloric acid, and a watch glass containing calcium carbonate. The total mass on each scale is 804.5 grams. The scale at left has one large chunk of calcium carbonate, the scale at right has the same mass divided into small chunks. These are added to the acid, where a reaction takes place, producing carbon dioxide gas, which bubbles off, and also water and calcium chloride in solution. It can be seen that the scale at right loses mass more quickly than the one at left, as it produces carbon dioxide more quickly. This is because the small chunks of calcium carbonate had a larger surface area for the acid to attack.