Question 1

Which of the following best explains why the burning of coal is more dangerous to touch than the rusting of iron, even though both are exothermic reactions?

Accepted Answer

Burning of coal releases heat much more rapidly due to a faster reaction rate.

Question 2

A reaction is found to have the rate law $$	ext{rate} = k[	ext{A}]^2[	ext{B}]. $$What is the overall order of the reaction?

Accepted Answer

Third order

Question 3

Which factor does NOT increase the rate of a chemical reaction?

Accepted Answer

Decreasing the temperature

Question 4

For a zero-order reaction, which of the following is the correct integrated rate law?

Accepted Answer

$$[A]_t = [A]_0 - kt$$

Question 5

Which statement about catalysts is TRUE?

Accepted Answer

Catalysts provide a new pathway with lower activation energy.

Question 6

The half-life of a first-order reaction is given by which equation?

Accepted Answer

$$t_{1/2} = \dfrac{0.693}{k}$$

Question 7

According to collision theory, which condition is NOT necessary for a successful reaction between two molecules?

Accepted Answer

Molecules must collide at a low temperature.

Question 8

For the reaction $$aA + bB ightarrow cC + dD$$ with the rate law $$	ext{rate} = k[	ext{B}]^2$$, what is the order with respect to A and B?

Accepted Answer

Zero order with respect to A, second order with respect to B

Question 9

Which graph would you expect for a plot of $$\ln[A]$$ versus time for a first-order reaction?

Accepted Answer

A straight line with a negative slope

Question 10

A pharmaceutical reaction is found to be second order. If the initial concentration of reactant A is doubled, how does the initial rate change?

Accepted Answer

It increases by a factor of 4

Question 11

Which of the following is the correct expression for the average rate of change in concentration of reactant A over a time interval?

Accepted Answer

$$\dfrac{\Delta [A]}{\Delta t}$$

Question 12

Which of the following statements about reaction order is correct?

Accepted Answer

The reaction order must be determined experimentally.

Question 13

For a second-order reaction, what is the correct integrated rate law?

Accepted Answer

$$\dfrac{1}{[A]_t} = \dfrac{1}{[A]_0} + kt$$

Question 14

Which of the following best describes the effect of a catalyst on a reaction coordinate diagram?

Accepted Answer

It lowers the activation energy ($$E_a) $$and provides an alternative pathway.

Question 15

Which of the following is the correct half-life equation for a zero-order reaction?

Accepted Answer

$$t_{1/2} = \dfrac{[A]_0}{2k}$$

Question 16

In a pharmaceutical process, the rate law is found to be $$	ext{rate} = k[	ext{A}]. If $$the concentration of A is reduced by half, what happens to the rate?

Accepted Answer

The rate is reduced to half its original value.

Question 17

Which of the following is TRUE about the activated complex (transition state) in a chemical reaction?

Accepted Answer

It is the arrangement of atoms at the highest potential energy along the reaction coordinate.

Question 18

For a reaction $$A ightarrow 	ext{products}$$, the rate law is $$	ext{rate} = k[A]^0. $$Which statement is correct?

Accepted Answer

The rate is constant and independent of [A].

Question 19

Which of the following is a correct statement about the rate-determining step in a multi-step reaction mechanism?

Accepted Answer

It controls the overall rate law of the reaction.

Chemical Kinetics: Rates, Mechanisms, and Reaction Orders

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