Question

a change in which factor will affect the rate of reaction only when gases are involved?
○ temperature
○ pressure
○ surface area
○ concentration

Explanation:

• Temperature affects reaction rates for all phases (solid, liquid, gas) by changing particle kinetic energy.
• Pressure affects reaction rates only for gaseous reactions because changing pressure changes the concentration of gas particles (by changing volume, which affects the number of particles per unit volume). For solids and liquids, pressure changes have negligible effect on concentration.
• Surface area affects reactions involving solids (more surface area means more particle collisions), not specific to gases.
• Concentration affects reaction rates for solutions and gases (by changing particle number per volume), not unique to gases.

Answer:

B. pressure