Name three factors that can increase the rate of a chemical reaction and briefly explain how they do so.

• A. Lower temperature slows collisions; lower concentration reduces contact; smaller surface area increases contact; catalysts increase activation energy.
• B. Higher temperature makes collisions less energetic; higher concentration decreases collision frequency.
• C. Higher temperature; higher concentration; larger surface area; catalysts lower activation energy.
• D. Only adding a catalyst affects rate; the others have no effect.

Answer: (C)