How does an increase in surface area affect the reaction rate?

An increase in surface area positively impacts the reaction rate because it allows for more reactant particles to come into contact with each other. In the context of chemical reactions, the rate is often influenced by how frequently reactants collide. When a solid reactant is broken into smaller pieces, the number of exposed particles increases, leading to a greater likelihood of successful collisions with other reactant molecules.

For example, consider a reaction involving a solid reactant in the form of a block versus the same reactant in powdered form. The powdered form has a significantly larger surface area, which enhances the rate of reaction because there are more opportunities for reactants to interact. This principle is crucial in various applications, such as catalysts and reaction mechanisms, where maximizing surface area can lead to faster reactions.

The other options suggest that either the reaction rate is unchanged or decreases, which contradicts the fundamental principles of collision theory in chemistry. In most cases, increasing surface area accelerates the reaction by increasing collision frequency, thus affirming that a larger surface area indeed increases the reaction rate.