Q: For the reaction $$aA + bB \rightarrow cC + dD$$, the general rate expression is:

$$\text{Rate} = -\frac{1}{a}\frac{d[A]}{dt} = -\frac{1}{b}\frac{d[B]}{dt} = \frac{1}{c}\frac{d[C]}{dt} = \frac{1}{d}\frac{d[D]}{dt}$$

Question 1

Which of the following factors will NOT affect the rate of a chemical reaction?

Accepted Answer

The color of the reactants

Question 2

A medicine in powdered form dissolves more quickly than in tablet form. This is primarily due to which factor affecting reaction rate?

Accepted Answer

Increased surface area increases reaction rate

Question 3

For the reaction $$2HI(g) \rightarrow H_2$(g) + I_2$(g)$$, how is the rate of disappearance of HI related to the rate of appearance of $$H_2$$?

Accepted Answer

The rate of disappearance of HI is twice the rate of appearance of $$H_2$$

Question 4

Given the reaction $$2O_3(g) ightarrow 3O_2(g)$$, if the rate of appearance of $$O_2 is$$ $$6.0 	imes 10$$^{-5}$$ M/s, what is the rate of disappearance of O_3$?

Accepted Answer

$$4.0 	imes 10$$^{-5}$$ M/s

Question 5

Which statement about reaction orders is TRUE?

Accepted Answer

Reaction orders must be determined experimentally and do not necessarily match the stoichiometric coefficients.

Question 6

For a first-order reaction, if the concentration of reactant A is halved, what happens to the rate?

Accepted Answer

The rate is halved.

Question 7

Consider the rate law $$	ext{Rate} = k[A]^2. If$$ $$[A] is $$doubled, by what factor does the rate increase?

Accepted Answer

The rate increases by a factor of 4.

Question 8

A reaction has the rate law $$	ext{Rate} = k[A]^0. $$Which of the following is TRUE?

Accepted Answer

The rate is independent of $$[A].$$

Question 9

Given the following data for the reaction $$A(g) + B(g) \rightarrow C(g) + D(g)$$:
Exp 1: $$[A]=0.25 M$$, $$[B]=0.40 M$$, Rate = $$x$$
Exp 2: $$[A]=0.75 M$$, $$[B]=0.40 M$$, Rate = $$3x$$
What is the order with respect to A?

Accepted Answer

First order

Question 10

For the reaction $$2NO(g) + 2H_2(g) ightarrow N_2$(g) + 2H_2O(g)$$, the following data are collected:
Exp 1: $$[NO]=0.10 M$$, $$[H_2$]=0.10 M$$, Rate = $$1.23 	imes 10$$^{-3}$$ M/s
Exp 2: $$[NO]=0.20$$ M, $$[$$H_2$$]=0.10$$ M, Rate = 4.92$$ 	imes $$10^{-3} M/s
$$What is the order with respect to NO?

Accepted Answer

Second order

Question 11

For the reaction $$2HgCl_2 + CO \rightarrow Hg_2Cl_2 + 2CO_2 + 2Cl^-$$, the initial rate quadruples when $$[CO] is $$doubled. What is the order with respect to CO?

Accepted Answer

Second order

Question 12

The rate law for a reaction is $$	ext{Rate} = k[A][B]^2. $$What are the units of the rate constant $$k$$?

Accepted Answer

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

Question 13

If a reaction is third order overall, which of the following could be its rate law?

Accepted Answer

$$	ext{Rate} = k[A]^2[B]$$

Question 14

A catalyst increases the rate of a reaction by:

Accepted Answer

Lowering the activation energy

Question 15

Which of the following best describes the instantaneous rate of a reaction?

Accepted Answer

The rate at a specific moment, determined by the slope of the concentration vs. time curve

Question 16

For the reaction $$aA + bB \rightarrow cC + dD$$, the general rate expression is:

Accepted Answer

$$	ext{Rate} = -\frac{1}{a}\frac{d[A]}{dt} = -\frac{1}{b}\frac{d[B]}{dt} = \frac{1}{c}\frac{d[C]}{dt} = \frac{1}{d}\frac{d[D]}{dt}$$

Question 17

A reaction has a rate constant $$k = 2.7 	imes 10$$^{-4}$$ \mathrm{M}^{-1}\mathrm{s}^{-1}$$ and the rate law $$	ext{Rate} = k[A][B]. $$What is the rate when $$[A] = 0.100 M $$and $$[B] = 0.100 M$$?

Accepted Answer

$$2.7 	imes 10$$^{-6}$$ M/s

Question 18

Which of the following statements about the rate constant $$k is $$correct?

Accepted Answer

The magnitude of $$k$$ increases with temperature

Question 19

In a real-world scenario, why does milk spoil more quickly at room temperature than in a refrigerator?

Accepted Answer

Higher temperature increases the rate constant $$k$$, speeding up the reaction

Chemical Kinetics: Rates, Mechanisms, and Rate Laws

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