Unit 5 Chemistry Review

If the reaction occurs in a single elementary step that is a three-body molecular collision, then which of the following is the equation for the elementary step?

2NO + O2 -> 2NO2

Based on the proposed mechanism, what is the balanced chemical equation for the overall reaction?

2O3(g) -> 3O2(g)

What is the rate of disappearance of O2(g) under the same conditions?

Because two molecules of NO are consumed per molecule of O2, the rate of disappearance of O2(g) is 2.5 * 10-5 Ms-1.

Based on the models, which of the following represents a species that acts as a catalyst for the reaction?

C

If both experiments are carried out with finely powdered samples of the solid and 50 mL of HCl (aq), which experiment, if any, will have the faster initial rate of formation of CO2(g) and why?

CO2(g) will be formed at a faster rate in experiment 2 because more H+ particles can react per unit time.

Which graph best represents the changes in concentration of O2(g), and why?

Graph 1, because the rate of O2 consumption is half the rate at which NO is consumed; two molecules of NO react for each molecule of O2 that reacts.

Based on this information, which of the following provides the best reason for the use of Ru (s) for the synthesis of NH3?

It provides a reaction path with a lower activation energy.

Which of the following changes should be made to the graph to explain the increase in the rate of the reaction if the only change in experimental conditions is the addition of a catalyst?

Line B will move to the left because a larger fraction of the Y2 molecules will have the minimum energy to overcome the activation energy barrier.

Based on the graph, which of the following statements best explains why the rates of disappearance of NO2(g) are different at temperature 2 and temperature 1?

NO2(g) is consumed at a faster rate at temperature 2 because more molecules possess energies at or above the minimum energy required for a collision to lead to a reaction compared to temperature 1.

Based on the information, which of the following is the initial rate law for the reaction?

Rate= k[Br2][NO]2

Which of the following represents a rate law for the overall reaction that is consistent with the proposed mechanism?

Rate= k[H2][ICl]2

Which of the following initial rate law expressions is consistent with this proposed mechanism?

Rate= k[H2][NO]2

Which of the following rate laws is consistent with the proposed mechanism?

Rate= k[HBr][O2]

Based on the information, which of the following is the rate law expression for the reaction?

Rate= k[HO2]2

Which of the following rate laws is consistent with this mechanism?

Rate= k[NO2][F2]

Based on the data given in the table above, which of the following is the rate law expression for the reaction, and why?

Rate= k[NO]2[Cl2], because the initial rate quadrupled when [NO] was doubled and doubled when [Cl2] was doubled.

Based on the proposed mechanism, which of the following is the rate-law expression for the destruction of O3?

Rate= k[O3][Cl]

Based on the data in the table, which statement is correct?

Since the rate law can be expressed as rate= k[A2][B], doubling the concentrations of A2 and B will quadruple the rate of the reaction.

The reaction is carried out at constant temperature inside a rigid container. Based on this mechanism, which of the following is the most likely reason for the different rates of step 1 and step 2?

The amount of energy for a successful collision between H2 and ICl is greater than the amount of energy required for a successful collision between HI and ICl.

Which of the following correctly identifies both the chemical equation for step 1 and the rate law for the overall reaction?

The chemical equation for step 1 is 2NO2(g) -> NO(g) + NO3(g), and the rate law is rate= [NO2]2.

Based on the proposed mechanism, which of the following best describes the concentration of the species represented above as the reaction occurs?

The concentration is very low for the duration of the reaction.

Which statement provides the best comparison of the initial rate of formation of AB in experiments 1 and 2?

The initial rate of formation of AB is faster in experiment 1 than in experiment 2 because at a higher pressure the collisions between A2 and B2 molecules would have been more frequent, increasing the probability of a successful collision.

Which of the following represents the overall chemical equation for the reaction and the the rate law for elementary step 2?

The overall reaction is H2(g) + 2ICl(g) -> 2HCl(g) + I2(g); the rate law for step 2 is rate= k[HI][ICl]

If the concentration of [S2O82-] is doubled while keeping [I-] constant, which of the following experimental results is predicted based on the rate law, and why?

The rate of reaction will double, because the rate is directly proportional to [S2O82-].

Based on this information, which of the following best explains the large increase in the rate of hydrolysis that occurs with the addition of sucrase?

The reaction proceeds through a different reaction path with a lower activation energy in which the sucrase-sucrose complex is formed as an intermediate.

Which of the following best identifies the rate constant k for the reaction based on the information in the plot of ln[H2O2] versus time (t)?

k= -(slope of plot)