Answer:
Surface area
Explanation:
The rate of a chemical reaction is increased when the surface area of a solid reactant is increased. This can be done by cutting the substance into small pieces, or by grinding it into a powder. If the surface area of a reactant is increased, it implies more particles are exposed to the other reactant.
When a seltzer tablet is ground into powder, the idea is to expose more of its surface to the other reactant. Since rate reaction depends on effective collision between reactants, more exposed particles implies a greater degree of collision between reactants and a faster rate of reaction.
