Question

what change causes the reaction to change from the curve labeled c to the curve labeled b? the surface area of the reactants is increased. the temperature of the system is increased. the concentration of the reactants is increased. a catalyst is added to the system.

Explanation:

To determine the change from curve C to B, we analyze the potential energy diagram. A catalyst lowers the activation energy (the peak of the curve) without changing the reactant (R) or product (P) energy.

• Increasing surface area, temperature, or concentration affects reaction rate but not activation energy (these changes don’t lower the peak like curve B does relative to C).
• Adding a catalyst reduces the activation energy, matching the shift from C (higher activation energy) to B (lower activation energy).

Answer:

D. A catalyst is added to the system.