Question 1

Which of the following best describes the main purpose of studying chemical kinetics?

Accepted Answer

To understand the speed of chemical reactions and how to control it

Question 2

Consider the reaction: $$\mathrm{N_2$ + 3H_2 \rightarrow 2NH_3}. If $$you start with 1 mol of $$\mathrm{N_2$}$$ and 3 mol of $$\mathrm{H_2$}$$, what is the maximum extent of reaction $$\xi_{max}$$ possible?

Accepted Answer

$$\xi_{max} = 1$$ mol$$\ \mathrm{N_2$} or$$ $$\xi_{max} = 2$$ mol$$\ \mathrm{NH_3$}$$

Question 3

Which of the following statements about reaction intermediates is correct?

Accepted Answer

They are formed and consumed during the reaction mechanism

Question 4

For the reaction $$2\mathrm{NO_2$}(g) \rightarrow 2\mathrm{NO}(g) + \mathrm{O_2$}(g)$$, the rate law is $$v = k[\mathrm{NO_2$}]^2. $$What is the overall order of this reaction?

Accepted Answer

Order 2

Question 5

A catalyst increases the rate of a reaction by:

Accepted Answer

Lowering the activation energy $$E_a$$

Question 6

Given the Arrhenius equation $$k = A e$$^{-E_a/(RT)}$$, what is the effect of increasing the temperature T$ on the rate constant k$?

Accepted Answer

It increases $$k$$

Question 7

Which of the following is true about the molecularity of an elementary reaction?

Accepted Answer

It refers to the number of molecules involved in a single collision event

Question 8

In the industrial synthesis of ammonia ($$\mathrm{N_2$ + 3H_2 \rightarrow 2NH_3}$$), which of the following expressions correctly relates the rate of disappearance of $$\mathrm{H_2$} to $$the rate of formation of $$\mathrm{NH_3$}$$?

Accepted Answer

$$v(\mathrm{NH_3$}) = \frac{2}{3}v(\mathrm{H_2$})$$

Question 9

A reaction has an activation energy $$E_a = 76\ \mathrm{kJ\ $$mol^{-1}$$}$$ and a catalyst lowers it to $$E'_a = 8\ \mathrm{kJ\ $$mol^{-1}$$}. $$What is the main effect of this change?

Accepted Answer

The reaction rate increases dramatically

Question 10

Which of the following best describes the difference between a reaction intermediate and a transition state?

Accepted Answer

A reaction intermediate is a real, isolable species; a transition state is not

Question 11

Given the following experimental data for the reaction $$2\mathrm{NO}(g) + \mathrm{Cl_2$}(g) ightarrow 2\mathrm{NOCl}(g)$$:

Experiment 1: $$[\mathrm{NO}] = 0.0125$$ mol/L, $$[\mathrm{Cl_2$}] = 0.0255$$ mol/L, $$v = 2.27 	imes 10$$^{-5}$$ mol/L·s
Experiment 2: $$[\mathrm{NO}] = 0.0125$$ mol/L, $$[\mathrm{$$Cl_2$$}] = 0.0510$$ mol/L, v = 4.55$$ 	imes $$10^{-5}$$ mol/L·s
Experiment 3: $$[\mathrm{NO}] = 0.0250$$ mol/L, $$[\mathrm{Cl_2$}] = 0.0255$$ mol/L, $$v = 9.08 	imes 10$$^{-5}$$ mol/L·s

What is the rate law for this reaction?

Accepted Answer

$$v = k[\mathrm{NO}]^2[\mathrm{Cl_2$}]$$

Question 12

Which of the following is NOT a property of a catalyst?

Accepted Answer

It changes the equilibrium constant

Question 13

Which of the following best describes a unimolecular elementary reaction?

Accepted Answer

A reaction involving the transformation of a single molecule

Question 14

In a reaction profile diagram, what does the height of the energy barrier between reactants and products represent?

Accepted Answer

The activation energy $$E_a$$

Question 15

Which of the following statements about the effect of temperature on reaction rate is correct?

Accepted Answer

Increasing temperature increases the number of effective collisions

Question 16

A reaction is said to be under kinetic control when:

Accepted Answer

The product formed fastest predominates

Question 17

Which of the following is a correct statement about the SN1 reaction mechanism?

Accepted Answer

It involves a reaction intermediate

Question 18

For the reaction $$\mathrm{C_2H_6}(g) \rightarrow 2\mathrm{CH_3$}^\cdot(g)$$, the rate law is $$v = k[\mathrm{C_2H_6}]. $$What is the unit of the rate constant $$k$$?

Accepted Answer

$$\mathrm{s$$^{-1}$$}$$

Question 19

Which of the following is a real-world example of a heterogeneous catalyst?

Accepted Answer

Platinum in a car exhaust catalytic converter

Chemical Kinetics: Principles, Rate Laws, Mechanisms, and Catalysis

Study Guide - Practice Questions

Study Guide - Flashcards