Q: Given the reaction $$A \rightarrow B$$, the concentration of A decreases from $$0.800\ \text{M} to$$ $$0.600\ \text{M} in$$ $$100\ \text{s}. $$What is the average rate of disappearance of A?

$$2.00 \times 10$$^{-3}$$\ \text{M/s}$$

Question 1

Which of the following best defines chemical kinetics?

Accepted Answer

The study of how quickly reactions occur.

Question 2

Which of the following is the correct unit for reaction rate when concentration is measured in molarity and time in seconds?

Accepted Answer

$$\frac{	ext{M}}{	ext{s}}$$

Question 3

For the reaction $$A \rightarrow B$$, which expression correctly represents the rate of disappearance of A?

Accepted Answer

$$-\frac{\Delta [A]}{\Delta t}$$

Question 4

Which of the following factors does NOT generally increase the rate of a chemical reaction?

Accepted Answer

Decreasing the concentration of reactants

Question 5

A catalyst increases the rate of a reaction by:

Accepted Answer

Providing a surface for molecules to react and lowering activation energy

Question 6

For the reaction $$2	ext{O}_3 (g) ightarrow 3	ext{O}_2 (g)$$, if the rate of appearance of $$	ext{O}_2 is$$ $$4.50\ 	ext{M/s}$$, what is the rate of disappearance of $$	ext{O}_3$$?

Accepted Answer

$$3.00\ 	ext{M/s}$$

Question 7

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

Accepted Answer

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

Question 8

Why does increasing the temperature generally increase the rate of a chemical reaction?

Accepted Answer

It increases the number of collisions with sufficient energy to react.

Question 9

Which of the following is a correct statement about the effect of a catalyst?

Accepted Answer

A catalyst lowers the activation energy, increasing the reaction rate.

Question 10

Given the reaction $$A ightarrow B$$, the concentration of A decreases from $$0.800\ 	ext{M} to$$ $$0.600\ 	ext{M} in$$ $$100\ 	ext{s}. $$What is the average rate of disappearance of A?

Accepted Answer

$$2.00 	imes 10$$^{-3}$$\ 	ext{M/s}$$

Question 11

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

Accepted Answer

The rate at the very beginning of the reaction, often determined by the slope at $$t=0$$

Question 12

Which of the following changes would NOT increase the frequency of effective collisions in a reaction mixture?

Accepted Answer

Decreasing the temperature

Question 13

For the reaction $$2A ightarrow 3B$$, if the rate of disappearance of A is $$0.20\ 	ext{M/s}$$, what is the rate of appearance of B?

Accepted Answer

$$0.30\ 	ext{M/s}$$

Question 14

Which of the following is the best example of a mechanism in chemical kinetics?

Accepted Answer

A series of elementary steps that show how a reaction occurs

Question 15

If a reaction is carried out in a solution and the solvent is changed from water to ethanol, which factor affecting reaction rate is being altered?

Accepted Answer

State of matter

Question 16

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

Accepted Answer

It is calculated over a specific time interval.

Chemical Kinetics: Reaction Rates and Factors Affecting Rates

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