Question 1

Explain the concepts of a mechanism and a rate-determining step in a chemical reaction.

Accepted Answer

A reaction mechanism is the exact molecular pathway that starting materials follow on their way to becoming products. The overall reaction is the sum of the elementary steps in the mechanism. The rate-determining step is the slowest step in the reaction mechanism. The overall reaction cannot go faster than the rate-determining step.

Question 2

Determine the rate of a reaction based on the rate of change of concentration of a reactant or a product.

Accepted Answer

The reaction rate can be expressed using the rate of change of concentration of any of the reagents.

Question 3

Determine the rate law, given the mechanism and knowledge of the relative rates of steps of a reaction.

Accepted Answer

A reaction rate depends on the concentrations of the reactants as expressed by the rate law for that reaction. The order of a reactant often differs from its stoichiometric coefficient.

Question 4

Determine rate laws from concentration versus time data.

Accepted Answer

The answer of Determine rate laws from concentration versus time...

Question 5

Show that the mechanism and rate law are closely related.

Accepted Answer

The answer of Show that the mechanism and rate law...

Question 6

Explain and quantify the effects of temperature on a reaction rate.

Accepted Answer

The answer of Explain and quantify the effects of temperature...

Question 7

Explain the mechanisms by which catalysts function.

Accepted Answer

The answer of Explain the mechanisms by which catalysts function....

Question 8

Which of the following are bimolecular processes? I. II. NO $\rarr$ ONNO III. H₂C = CHCH₃ + H₂SO₄ $\rarr$ CH₃CH(OSO₂(OH))CH₃ IV. V. H₂ $\rarr$ 2 H•

Accepted Answer

The answer of Which of the following are bimolecular processes?
I....

Question 9

Which of the following is an elementary reaction?

Accepted Answer

The answer of Which of the following is an elementary...

Question 10

The formation of chlorocarbon solvents such as CH₂Cl₂ proceeds through the reaction of chlorine with methane. Which of the following is a unimolecular reaction in the mechanism?

Accepted Answer

Option D represents a unimolecular reaction because it involves the decomposition of a single molecule (Cl_2) into two products (2 Cl•) without the involvement of another reactant molecule in the rate-determining step.

Question 11

It has been suggested that the decomposition of NO₂ occurs via the following mechanism: NO₂ $\rarr$ NO + O (Rxn I) O + NO₂ $\rarr$ 2NO + O₂(Rxn II) Predict the rate determining step.

Accepted Answer

C) Rxn I; O is highly reactive and thus Rxn II will be very fast.

Question 12

You are running late for a basketball game on your campus and you are thinking about what will be the rate determining step for attending the basketball game? Which of the following will be your rate determining step?

Accepted Answer

The rate determining step is the slowest step that determines the overall rate of a process. In this context, walking/driving to the game (C) is likely the longest and most variable part of the process, affecting how quickly you can attend the game.

Question 13

Which of the following sketches shows the proper orientation of molecules for CO₂ reacting with NO to make NO₂ and CO?

Accepted Answer

The answer of Which of the following sketches shows the...

Question 14

The synthesis of nitrogen monoxide proceeds by the reaction of ammonia with oxygen as shown in the following unbalanced reaction: NH₃(g) + O₂(g) $\rarr$ NO(g) + H₂O(g)If O₂ is being consumed at a rate of 32 mole/sec, what is the rate of NO production?

Accepted Answer

The answer of The synthesis of nitrogen monoxide proceeds by...

Question 15

Consider the aqueous phase reaction between the dichromate anion and iron (II) cations:14 H₃O⁺(aq) + Cr₂O₇^2-+ 6Fe²⁺(aq) $\rarr$ 2Cr³⁺(aq) + 21H₂OWhat is the reaction rate expressed in terms of changing H₃O⁺concentration?

Accepted Answer

The answer of Consider the aqueous phase reaction between the...

Question 16

Consider the aqueous phase reaction between hydrogen gas and liquid bromine:H₂(g) + Br₂(g) $\rarr$ 2HBr(g)Which of the following expressions accurately express the rate of the above reaction? I. Reaction rate = II. Reaction rate = III. Reaction rate = IV. Reaction rate =

Accepted Answer

The answer of Consider the aqueous phase reaction between hydrogen...

Question 17

Consider the aqueous phase reaction between the dichromate anion and iron (II) cations:14 H₃O⁺(aq) + Cr₂O₇^2-+ 6Fe²⁺(aq) $\rarr$ 2Cr³⁺(aq) + 21H₂OWhat is the rate of increase of Cr³⁺ concentration expressed in terms of changing H₃O⁺concentration?

Accepted Answer

The answer of Consider the aqueous phase reaction between the...

Question 18

Cyclohexane is manufactured from the reaction of benzene with hydrogen: C₆H₆(g) + 3 H₂(g) $\rarr$ C₆H₁₂(g) If the initial concentration of hydrogen was 1.5 M and 5 minutes later the hydrogen concentration is 0.34 M, what is the average rate of disappearance of hydrogen?

Accepted Answer

The answer of Cyclohexane is manufactured from the reaction of...

Question 19

Cyclohexane is manufactured from the reaction of benzene with hydrogen: C₆H₆(g) + 3 H₂(g) $\rarr$ C₆H₁₂(g) If the initial concentration of hydrogen was 1.5 M and 5 minutes later the hydrogen concentration is 0.34 M, what is the average rate of appearance of cyclohexane?

Accepted Answer

The average rate of appearance of cyclohexane can be calculated based on the change in concentration of hydrogen since 3 moles of hydrogen are consumed for every mole of cyclohexane produced. The change in hydrogen concentration is 1.5 M - 0.34 M = 1.16 M over 5 minutes. Since the stoichiometry requires 3 moles of hydrogen for 1 mole of cyclohexane, the rate of appearance of cyclohexane is (1.16 M / 3) / 5 min = 0.077 M/min or 7.7 x 10^-2 M/min.

Question 20

NO₂ decomposes to form NO and O₂. The concentration of NO₂ is monitored and found to be 2.1x10^-2M after 15 seconds and 1.8 x10^-2 M after 20 seconds. What is the average rate of appearance of O₂ over this time period?

Accepted Answer

The answer of NO₂ decomposes to form NO and O₂....

Quiz 13: Kinetics: Mechanisms and Rates of Reactions

Explain the concepts of a mechanism and a rate-determining step in a chemical reaction.

Determine the rate of a reaction based on the rate of change of concentration of a reactant or a product.

Determine the rate law, given the mechanism and knowledge of the relative rates of steps of a reaction.

Determine rate laws from concentration versus time data.

Show that the mechanism and rate law are closely related.

Explain and quantify the effects of temperature on a reaction rate.

Explain the mechanisms by which catalysts function.

Which of the following is an elementary reaction?

The formation of chlorocarbon solvents such as CH₂Cl₂ proceeds through the reaction of chlorine with methane. Which of the following is a unimolecular reaction in the mechanism?

It has been suggested that the decomposition of NO₂ occurs via the following mechanism: NO₂ $\rarr$ NO + O (Rxn I) O + NO₂ $\rarr$ 2NO + O₂(Rxn II) Predict the rate determining step.

You are running late for a basketball game on your campus and you are thinking about what will be the rate determining step for attending the basketball game? Which of the following will be your rate determining step?

Which of the following sketches shows the proper orientation of molecules for CO₂ reacting with NO to make NO₂ and CO?

The synthesis of nitrogen monoxide proceeds by the reaction of ammonia with oxygen as shown in the following unbalanced reaction: NH₃(g) + O₂(g) $\rarr$ NO(g) + H₂O(g) If O₂ is being consumed at a rate of 32 mole/sec, what is the rate of NO production?

Consider the aqueous phase reaction between the dichromate anion and iron (II) cations:14 H₃O⁺(aq) + Cr₂O₇^2-+ 6Fe²⁺(aq) $\rarr$ 2Cr³⁺(aq) + 21H₂OWhat is the reaction rate expressed in terms of changing H₃O⁺concentration?

Consider the aqueous phase reaction between the dichromate anion and iron (II) cations:14 H₃O⁺(aq) + Cr₂O₇^2-+ 6Fe²⁺(aq) $\rarr$ 2Cr³⁺(aq) + 21H₂OWhat is the rate of increase of Cr³⁺ concentration expressed in terms of changing H₃O⁺concentration?

Cyclohexane is manufactured from the reaction of benzene with hydrogen: C₆H₆(g) + 3 H₂(g) $\rarr$ C₆H₁₂(g) If the initial concentration of hydrogen was 1.5 M and 5 minutes later the hydrogen concentration is 0.34 M, what is the average rate of disappearance of hydrogen?

Cyclohexane is manufactured from the reaction of benzene with hydrogen: C₆H₆(g) + 3 H₂(g) $\rarr$ C₆H₁₂(g) If the initial concentration of hydrogen was 1.5 M and 5 minutes later the hydrogen concentration is 0.34 M, what is the average rate of appearance of cyclohexane?

NO₂ decomposes to form NO and O₂. The concentration of NO₂ is monitored and found to be 2.1x10^-2M after 15 seconds and 1.8 x10^-2 M after 20 seconds. What is the average rate of appearance of O₂ over this time period?

Quiz 13: Kinetics: Mechanisms and Rates of Reactions

Explain the concepts of a mechanism and a rate-determining step in a chemical reaction.

Determine the rate of a reaction based on the rate of change of concentration of a reactant or a product.

Determine the rate law, given the mechanism and knowledge of the relative rates of steps of a reaction.

Determine rate laws from concentration versus time data.

Show that the mechanism and rate law are closely related.

Explain and quantify the effects of temperature on a reaction rate.

Explain the mechanisms by which catalysts function.

Which of the following are bimolecular processes? I. II. NO →\rarr→ ONNO III. H2C = CHCH3 + H2SO4 →\rarr→ CH3CH(OSO2(OH) ) CH3 IV. V. H2 →\rarr→ 2 H•

Which of the following is an elementary reaction?

The formation of chlorocarbon solvents such as CH2Cl2 proceeds through the reaction of chlorine with methane. Which of the following is a unimolecular reaction in the mechanism?

It has been suggested that the decomposition of NO2 occurs via the following mechanism: NO2 →\rarr→ NO + O (Rxn I) O + NO2 →\rarr→ 2NO + O2 (Rxn II) Predict the rate determining step.

You are running late for a basketball game on your campus and you are thinking about what will be the rate determining step for attending the basketball game? Which of the following will be your rate determining step?

Which of the following sketches shows the proper orientation of molecules for CO2 reacting with NO to make NO2 and CO?

The synthesis of nitrogen monoxide proceeds by the reaction of ammonia with oxygen as shown in the following unbalanced reaction: NH3(g) + O2(g) →\rarr→ NO(g) + H2O(g) If O2 is being consumed at a rate of 32 mole/sec, what is the rate of NO production?

Consider the aqueous phase reaction between the dichromate anion and iron (II) cations:14 H3O+(aq) + Cr2O72- + 6Fe2+(aq) →\rarr→ 2Cr3+(aq) + 21H2OWhat is the reaction rate expressed in terms of changing H3O+ concentration?

Consider the aqueous phase reaction between hydrogen gas and liquid bromine:H2(g) + Br2(g) →\rarr→ 2HBr(g) Which of the following expressions accurately express the rate of the above reaction? I. Reaction rate = II. Reaction rate = III. Reaction rate = IV. Reaction rate =

Consider the aqueous phase reaction between the dichromate anion and iron (II) cations:14 H3O+(aq) + Cr2O72- + 6Fe2+(aq) →\rarr→ 2Cr3+(aq) + 21H2OWhat is the rate of increase of Cr3+ concentration expressed in terms of changing H3O+ concentration?

Cyclohexane is manufactured from the reaction of benzene with hydrogen: C6H6(g) + 3 H2(g) →\rarr→ C6H12(g) If the initial concentration of hydrogen was 1.5 M and 5 minutes later the hydrogen concentration is 0.34 M, what is the average rate of disappearance of hydrogen?

Cyclohexane is manufactured from the reaction of benzene with hydrogen: C6H6(g) + 3 H2(g) →\rarr→ C6H12(g) If the initial concentration of hydrogen was 1.5 M and 5 minutes later the hydrogen concentration is 0.34 M, what is the average rate of appearance of cyclohexane?

NO2 decomposes to form NO and O2. The concentration of NO2 is monitored and found to be 2.1x10-2 M after 15 seconds and 1.8 x10-2 M after 20 seconds. What is the average rate of appearance of O2 over this time period?

The formation of chlorocarbon solvents such as CH₂Cl₂ proceeds through the reaction of chlorine with methane. Which of the following is a unimolecular reaction in the mechanism?

It has been suggested that the decomposition of NO₂ occurs via the following mechanism: NO₂ $\rarr$ NO + O (Rxn I) O + NO₂ $\rarr$ 2NO + O₂(Rxn II) Predict the rate determining step.

Which of the following sketches shows the proper orientation of molecules for CO₂ reacting with NO to make NO₂ and CO?

The synthesis of nitrogen monoxide proceeds by the reaction of ammonia with oxygen as shown in the following unbalanced reaction: NH₃(g) + O₂(g) $\rarr$ NO(g) + H₂O(g) If O₂ is being consumed at a rate of 32 mole/sec, what is the rate of NO production?

Consider the aqueous phase reaction between the dichromate anion and iron (II) cations:14 H₃O⁺(aq) + Cr₂O₇^2-+ 6Fe²⁺(aq) $\rarr$ 2Cr³⁺(aq) + 21H₂OWhat is the reaction rate expressed in terms of changing H₃O⁺concentration?

Consider the aqueous phase reaction between the dichromate anion and iron (II) cations:14 H₃O⁺(aq) + Cr₂O₇^2-+ 6Fe²⁺(aq) $\rarr$ 2Cr³⁺(aq) + 21H₂OWhat is the rate of increase of Cr³⁺ concentration expressed in terms of changing H₃O⁺concentration?

Cyclohexane is manufactured from the reaction of benzene with hydrogen: C₆H₆(g) + 3 H₂(g) $\rarr$ C₆H₁₂(g) If the initial concentration of hydrogen was 1.5 M and 5 minutes later the hydrogen concentration is 0.34 M, what is the average rate of disappearance of hydrogen?

Cyclohexane is manufactured from the reaction of benzene with hydrogen: C₆H₆(g) + 3 H₂(g) $\rarr$ C₆H₁₂(g) If the initial concentration of hydrogen was 1.5 M and 5 minutes later the hydrogen concentration is 0.34 M, what is the average rate of appearance of cyclohexane?

NO₂ decomposes to form NO and O₂. The concentration of NO₂ is monitored and found to be 2.1x10^-2M after 15 seconds and 1.8 x10^-2 M after 20 seconds. What is the average rate of appearance of O₂ over this time period?