Which of the following factors does NOT affect the rate of a chemical reaction?

• A. The concentration of reactants
• B. The temperature of the system
• C. The color of the reactants
• D. The presence of a catalyst

Answer: (C)

Verified step by step guidance

1. Understand that the rate of a chemical reaction depends on factors that influence how often and how effectively reactant molecules collide and react.
2. Recall that the concentration of reactants affects the rate because higher concentration means more molecules per unit volume, leading to more frequent collisions.
3. Recognize that temperature affects the rate by increasing the kinetic energy of molecules, which increases both the frequency and energy of collisions, making reactions faster.
4. Know that the presence of a catalyst affects the rate by providing an alternative reaction pathway with a lower activation energy, speeding up the reaction without being consumed.
5. Identify that the color of the reactants does NOT affect the reaction rate because color is a physical property related to light absorption and does not influence molecular collisions or energy directly.