Chemical Kinetics Fall 24

What is the relationship between concentration and reaction rate?

• Increasing the concentration of reactants typically increases the reaction rate.

• Decreasing the concentration of reactants typically increases the reaction rate.

• Concentration has no effect on reaction rate.

• Increasing the concentration of products typically increases the reaction rate.

What is meant by a reaction being first order with respect to a reactant?

• The rate of the reaction is directly proportional to the concentration of that reactant.

• The rate of the reaction is independent of the concentration of that reactant.

• The rate of the reaction decreases as the concentration of that reactant increases.

• The rate of the reaction is inversely proportional to the concentration of that reactant.

How does surface area affect reaction rates?

• Increasing surface area allows more collisions between reactants, thus increasing the reaction rate.

• Decreasing surface area reduces the number of collisions, slowing down the reaction rate.

• Surface area has no effect on reaction rates; only temperature matters.

• Increasing surface area decreases the reaction rate by spreading reactants too thin.

What is the effect of increasing temperature on reaction rates?

• Increasing temperature decreases reaction rates by reducing energy to the reactants.

• Increasing temperature generally increases reaction rates by providing more energy to the reactants.

• Increasing temperature has no effect on reaction rates.

• Increasing temperature only affects reaction rates in gaseous reactions.

What is the difference between a homogeneous and heterogeneous catalyst?

• A homogeneous catalyst is in the same phase as the reactants, while a heterogeneous catalyst is in a different phase.

• A homogeneous catalyst is a solid, while a heterogeneous catalyst is a liquid.

• A homogeneous catalyst speeds up reactions at lower temperatures, while a heterogeneous catalyst requires higher temperatures.

• A homogeneous catalyst is used in gas reactions, while a heterogeneous catalyst is used in liquid reactions.

What is the rate of the reaction BF3(g) + NH3(g) ⟶ F3BNH3(g) when [BF3] = 0.100 M and [NH3] = 0.500 M?

• 0.0500 M/s

• 0.1704 M/s

• 0.2500 M/s

• 0.3000 M/s

What is the rate law for the reaction BF3(g) + NH3(g) ⟶ F3BNH3(g)?

• rate = k[BF3]

• rate = k[NH3]

• rate = k[BF3][NH3]

• rate = k[BF3]^2[NH3]

Which factors increase the rate of a reaction?

• Increasing temperature

• Decreasing concentration

• Decreasing surface area

• All of the above

Explain the concept of a rate law.

• A rate law describes the temperature dependence of a reaction.

• A rate law expresses the relationship between the rate of a chemical reaction and the concentration of its reactants.

• A rate law is a mathematical equation that predicts the products of a reaction.

• A rate law indicates the physical state of the reactants in a reaction.

If the rate law is rate = k[A]^2[B], what must happen to [B] if [A] is doubled to keep the rate constant?

• [B] must be doubled.

• [B] must remain the same.

• [B] must be quartered.

• [B] must be halved.