How does a metal in powder form react faster with acid than the same metal in strips/blocks?

This is due to the metal in the powder form having a larger surface area. There are 4 ways to increase the rate of reaction. Increasing the concentration of the reactants, increasing the temperature, adding a catalyst or increasing the surface area of the reactants. The surface area is larger in powder form than in strips as the metal pieces are smaller, therefore there are more of them thus increasing the surface area. The larger the surface area, the more metal is exposed to the acid therefore increasing the rate of reaction.