Q: Given the reaction $$H_2(g$$) + $$Cl_2(g$$) \rightarrow 2HCl(g)$$, if $$[HCl]$$ increases from 0.000$$\,M$$ to 0.010$$\,M$$ in 20.00$$\,s$$, what is the average rate of reaction in terms of $$[HCl]$$?

$$5.0 \times 10$$^{-4}$$\,M/s$$

Question 1

Which of the following best describes the main goal of chemical kinetics?

Accepted Answer

To study the rates of chemical reactions and the factors that affect them.

Question 2

For the reaction $$2A + B \rightarrow P + 2Q$$, which expression correctly gives the average rate of reaction in terms of the change in concentration of $$A$$?

Accepted Answer

$$R_{avg} = -\frac{1}{2} \frac{\Delta [A]}{\Delta t}$$

Question 3

Why is it preferable to express the amount of product in a reaction as concentration $$[X]$$ when possible?

Accepted Answer

Because concentration is defined at every point in space and is an intensive property.

Question 4

Given the reaction $$H_2(g$$) + $$Cl_2(g$$) \rightarrow 2HCl(g)$$, if $$[HCl]$$ increases from 0.000$$\,M$$ to 0.010$$\,M$$ in 20.00$$\,s$$, what is the average rate of reaction in terms of $$[HCl]$$?

Accepted Answer

$$5.0 	imes 10$$^{-4}$$\,M/s$$

Question 5

Which of the following is true about the instantaneous rate of a reaction?

Accepted Answer

It is the derivative of concentration with respect to time at a specific moment.

Question 6

For a reaction $$A \rightarrow$$ Products with a rate law $$R = k[A]^n$$, if doubling $$[A]$$ causes the rate to quadruple, what is the order $$n$$?

Accepted Answer

$$n = 2$$

Question 7

Which of the following is NOT a valid operation when rearranging equations?

Accepted Answer

Multiplying only one term on one side by a number.

Question 8

The rate constant $$k$$ for a reaction is given by $$k = Ae$$^{-E_a/RT}$$. What does E_a$ represent?

Accepted Answer

The activation energy required for the reaction to proceed.

Question 9

For an ideal gas, the concentration $$[X]$$ can be related to its partial pressure $$P_X by $$which equation?

Accepted Answer

$$[X] = \frac{P_X}{RT}$$

Question 10

A reaction has the rate law $$R = k[A][B]^2. $$What are the units of $$k if $$the rate is in $$M/s$$?

Accepted Answer

$$M^{-2}s$$^{-1}$

Question 11

Which of the following statements about zero-order reactions is correct?

Accepted Answer

The rate is constant and independent of the concentration.

Question 12

If the half-life of a reaction increases as the initial concentration increases, what is the likely order of the reaction?

Accepted Answer

Second-order

Question 13

Which of the following is a correct integrated rate law for a first-order reaction?

Accepted Answer

$$\ln([A]_t) = \ln([A]_0) - kt$$

Question 14

A hot air balloon rises because the density of the gas inside is less than that of air. Which equation relates the density $$d of $$the gas to its molar mass $$M$$, pressure $$P$$, and temperature $$T$$?

Accepted Answer

$$d = \frac{PM}{RT}$$

Question 15

Which of the following best explains why the rate law for a reaction cannot generally be determined from the stoichiometric coefficients?

Accepted Answer

Because the rate law depends on the mechanism, not just the overall equation.

Question 16

If a reaction is first order in $$A$$ and zero order in $$B$$, what is the rate law?

Accepted Answer

$$R = k[A]$$

Question 17

Which of the following is a correct statement about the Arrhenius equation?

Accepted Answer

A plot of $$\ln k$$ versus $$1/T$$ yields a straight line.

Question 18

Which of the following is an intensive property?

Accepted Answer

Concentration

Question 19

A reaction has the rate law $$R = k[A]^2[B]. If$$ $$[A] is $$doubled and $$[B] is $$tripled, by what factor does the rate increase?

Accepted Answer

12

Question 20

Which of the following is the correct expression for the mean speed $$u of $$gas molecules with molar mass $$M at $$temperature $$T$$?

Accepted Answer

$$u = \sqrt{\frac{8RT}{\pi M}}$$

CHEM 1001 Section P: Chemical Dynamics – Chemical Kinetics and Mathematical Foundations

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