Question

Charcoal reacts with oxygen according to the equation C (s) + O2 (g) → CO2 (g). Which of the following changes would cause the greatest increase in the rate of reaction?

a. decreasing the concentration of O2(g)
b. decreasing the pressure of O2 (g)
c. using charcoal in powdered form
d. using charcoal in lump form

Answer 1

c. using charcoal in powdered form.

Step-by-step explanation:
The rate of a chemical reaction is affected by many factors, one of which is the surface area of the reactants. When the surface area of a solid reactant is increased, the rate of the reaction increases because it increases the number of reactive sites available for collision. Therefore, using charcoal in powdered form would increase the rate of reaction as the surface area of charcoal would be greater than in lump form.

On the other hand, decreasing the concentration of O2(g) would decrease the rate of reaction as there will be fewer O2 molecules for collision, decreasing the pressure of O2 (g) would affect the rate of reaction in a lesser extend, as pressure is not a major factor in this reaction. Using charcoal in lump form wouldn't affect the rate of the reaction as much as changing its form from lump to powdered.