Question 1

A certain reaction A F1F1F1S1F1F1F10 products is second order in A. If this reaction is 85% complete in 12 minutes, how long would it take for the reaction to be 15% complete?

Accepted Answer

A) 110 s 
B) 27 s 
C) 62 s 
D) 130 s 
E) 22 s 
A) 110 s 
B) 27 s 
C) 62 s 
D) 130 s 
E) 22 s

Question 2

When acetaldehyde at a pressure of 364 mmHg is introduced into an evacuated 500.mL flask at 518°C, the half-life for the second-order decomposition process, CH3CHO F1F1F1S1F1F1F10 CH4 + CO, is 410.s.What will the total pressure in the flask be after 1.00 hour?

Accepted Answer

A) 327 mmHg 
B) 654 mmHg 
C) 37 mmHg 
D) 691 mmHg 
E) 728 mmHg 
A) 327 mmHg 
B) 654 mmHg 
C) 37 mmHg 
D) 691 mmHg 
E) 728 mmHg

Question 3

Nitric oxide reacts with chlorine to form nitrosyl chloride, NOCl. Use the following data to determine the rate equation for the reaction. NO + 1/2Cl2 F1F1F1S1F1F1F10 NOCl

Accepted Answer

A) rate = k[NO] 
B) rate = k[NO][Cl2]1/2 
C) rate = k[NO][Cl2] 
D) rate = k[NO]2[Cl2] 
E) rate = k[NO]2[Cl2]2 
A) rate = k[NO] 
B) rate = k[NO][Cl2]1/2 
C) rate = k[NO][Cl2] 
D) rate = k[NO]2[Cl2] 
E) rate = k[NO]2[Cl2]2

Question 4

Use the table of data shown below to calculate the average rate of the reaction AF1F1F1S1F1F1F10B between 10 s and 20 s.

Accepted Answer

5 F1F1F1S1

Question 5

The reaction A + 2B F1F1F1S1F1F1F10 products has been found to have the rate law, rate = k[A] [B]2. While holding the concentration of A constant, the concentration of B is increased from x to 3x. Predict by what factor the rate of reaction increases.

Accepted Answer

A) 3 
B) 6 
C) 9 
D) 27 
E) 30 
A) 3 
B) 6 
C) 9 
D) 27 
E) 30

Question 6

The reaction C4H10 F1F1F1S1F1F1F10 C2H6 + C2H4 has an activation energy (Ea)of 350 kJ/mol, and the Ea of the reverse reaction is 260 kJ/mol. Estimate F1F1F1S1F1F1F10H, in kJ/mol, for the reaction as written above.

Accepted Answer

A) -90 kJ/mol 
B) +90 kJ/mol 
C) 350 kJ/mol 
D) -610 kJ/mol 
E) +610 kJ/mol 
A) -90 kJ/mol 
B) +90 kJ/mol 
C) 350 kJ/mol 
D) -610 kJ/mol 
E) +610 kJ/mol

Question 7

At 25°C the rate constant for the first-order decomposition of a pesticide solution is 6.40 F1F1F1S1F1F1F10 10-3 min-1. If the starting concentration of pesticide is 0.0314 M, what concentration will remain after 62.0 min at 25°C?

Accepted Answer

A) 1.14 F1F1F1S1F1F1F10 10-1 M 
B) 47.4 M 
C) -8.72.0 M 
D) 2.11 F1F1F1S1F1F1F10 10-2 M 
E) 2.68 F1F1F1S1F1F1F10 10-2 M 
A) 1.14 F1F1F1S1F1F1F10 10-1 M 
B) 47.4 M 
C) -8.72.0 M 
D) 2.11 F1F1F1S1F1F1F10 10-2 M 
E) 2.68 F1F1F1S1F1F1F10 10-2 M

Question 8

For the reaction BrO3- + 5Br-+ 6H+ $\rarr$ 3Br2 + 3H2O at a particular time, -$\Delta$[BrO3-]/$\Delta$t = 1.5 * 10-2 M/s. What is -$\Delta$[Br-]/$\Delta$t at the same instant?

Accepted Answer

A) 13 M/s 
B) 7.5 * 10-2 M/s 
C) 1.5 * 10-2 M/s 
D) 3.0 * 10-3 M/s 
E) 330 M/s 
A) 13 M/s 
B) 7.5 * 10-2 M/s 
C) 1.5 * 10-2 M/s 
D) 3.0 * 10-3 M/s 
E) 330 M/s

Question 9

The following reaction in aqueous solution was found to be first order in [OH-], first order in [C2H5Br], and inverse first order in Br-.
C2H5Br + OH- F1F1F1S1F1F1F10 C2H5OH + Br-
 Which one of the following mechanisms is consistent with the observed reaction order?

Accepted Answer

A) C2H5Br   C2H5+ + Br- fast C2H5+ + OH-   C2H5OH slow 
B) C2H5Br +H2O   C2H5OH + H+ + Br- slow H+ + OH- 
 
  H2O fast 
C) C2H5Br   C2H5+ + Br- slow C2H5+ + OH- 
 
  C2H5OH fast 
D) C2H5Br   C2H5+ + Br- slow OH- + Br-   HOBr fast
HOBr + C2H5+   C2H5OH + Br- fast 
A) C2H5Br   C2H5+ + Br- fast C2H5+ + OH-   C2H5OH slow 
B) C2H5Br +H2O   C2H5OH + H+ + Br- slow H+ + OH- 
 
  H2O fast 
C) C2H5Br   C2H5+ + Br- slow C2H5+ + OH- 
 
  C2H5OH fast 
D) C2H5Br   C2H5+ + Br- slow OH- + Br-   HOBr fast
HOBr + C2H5+   C2H5OH + Br- fast

Question 10

Use the following data to determine the rate law for the reaction shown below. 2NO + H2 F1F1F1S1F1F1F10 N2O + H2O

Accepted Answer

A) rate = k[NO] 
B) rate = k[NO]2 
C) rate = k[NO][H2] 
D) rate = k[NO]2[H2] 
E) rate = k[NO]2[H2]2 
A) rate = k[NO] 
B) rate = k[NO]2 
C) rate = k[NO][H2] 
D) rate = k[NO]2[H2] 
E) rate = k[NO]2[H2]2

Question 11

The reaction A + 2B F1F1F1S1F1F1F10 products was found to follow the rate law: rate = k[A]2[B].Predict by what factor the rate of reaction will increase when the concentration of A is doubled, the concentration of B is tripled, and the temperature remains constant.

Accepted Answer

A) 5 
B) 6 
C) 12 
D) 18 
E) None of these. 
A) 5 
B) 6 
C) 12 
D) 18 
E) None of these.

Question 12

At a particular temperature the first-order gas-phase reaction 2N2O5 F1F1F1S1F1F1F10 2N2O4 + O2 has a half-life for the disappearance of dinitrogen pentoxide of 3240 s. If 1.00 atm of N2O5 is introduced into an evacuated 5.00 L flask, what will be the total pressure of the gases in the flask after 1.50 hours?

Accepted Answer

A) 0.685 atm 
B) 1.00 atm 
C) 0.315 atm 
D) 1.68 atm 
E) 1.34 atm 
A) 0.685 atm 
B) 1.00 atm 
C) 0.315 atm 
D) 1.68 atm 
E) 1.34 atm

Question 13

The rate law predicted by the following two-step mechanism is rate = k[A][B].

Accepted Answer

A) True 
 B)False

Question 14

For the hypothetical reaction A + 3B F1F1F1S1F1F1F10 2C, the rate should be expressed as

Accepted Answer

A) rate = F1F1F1S1F1F1F10[A]/F1F1F1S1F1F1F10t 
B) rate = - F1F1F1S1F1F1F10[C]/F1F1F1S1F1F1F10t 
C) rate = -3 F1F1F1S1F1F1F10[B]/F1F1F1S1F1F1F10t 
D) rate = 1/2 F1F1F1S1F1F1F10[C]/F1F1F1S1F1F1F10t 
E) rate = 1/3 F1F1F1S1F1F1F10[B]/F1F1F1S1F1F1F10t 
A) rate = F1F1F1S1F1F1F10[A]/F1F1F1S1F1F1F10t 
B) rate = - F1F1F1S1F1F1F10[C]/F1F1F1S1F1F1F10t 
C) rate = -3 F1F1F1S1F1F1F10[B]/F1F1F1S1F1F1F10t 
D) rate = 1/2 F1F1F1S1F1F1F10[C]/F1F1F1S1F1F1F10t 
E) rate = 1/3 F1F1F1S1F1F1F10[B]/F1F1F1S1F1F1F10t

Question 15

A rate constant with the units L2 mol-2 s-1 is consistent with a

Accepted Answer

A) zero-order reaction. 
B) first-order reaction. 
C) second-order reaction. 
D) third-order reaction. 
E) fourth-order reaction. 
A) zero-order reaction. 
B) first-order reaction. 
C) second-order reaction. 
D) third-order reaction. 
E) fourth-order reaction.

Question 16

For the chemical reaction system described by the diagram below, which statement is true?   If the Ea for the forward reaction is 25 kJ/mol and the enthalpy of reaction is -95 kJ/mol, what is Ea for the reverse reaction?

Accepted Answer

A) 120 kJ/mol 
B) 70 kJ/mol 
C) 95 kJ/mol 
D) 25 kJ/mol 
E) -70 kJ/mol 
A) 120 kJ/mol 
B) 70 kJ/mol 
C) 95 kJ/mol 
D) 25 kJ/mol 
E) -70 kJ/mol

Question 17

For the following reaction, $\Delta$P(C6H14)/$\Delta$t was found to be -6.2 *10-3 atm/s. C6H14(g)$\rarr$ C6H6(g)+ 4H2(g)
Determine $\Delta$P(H2)/$\Delta$t for this reaction at the same time.

Accepted Answer

A) 6.2 * 10-3 atm/s 
B) 1.6 * 10-3 atm/s 
C) 2.5 * 10-2 atm/s 
D) -1.6 * 10-3 atm/s 
E) -2.5 * 10-2 atm/s 
A) 6.2 * 10-3 atm/s 
B) 1.6 * 10-3 atm/s 
C) 2.5 * 10-2 atm/s 
D) -1.6 * 10-3 atm/s 
E) -2.5 * 10-2 atm/s

Question 18

Which one of the following changes would alter the rate constant (k)for the reaction 2A + B F1F1F1S1F1F1F10 products?

Accepted Answer

A) increasing the concentration of A 
B) increasing the concentration of B 
C) increasing the temperature 
D) measuring k again after the reaction has run for a while 
A) increasing the concentration of A 
B) increasing the concentration of B 
C) increasing the temperature 
D) measuring k again after the reaction has run for a while

Question 19

An increase in the temperature of the reactants causes an increase in the rate of reaction. The best explanation for this behavior is that as the temperature increases,

Accepted Answer

A) the concentration of reactants increases. 
B) the activation energy decreases. 
C) the collision frequency increases. 
D) the fraction of collisions with total kinetic energy greater than Ea increases. 
E) the activation energy increases. 
A) the concentration of reactants increases. 
B) the activation energy decreases. 
C) the collision frequency increases. 
D) the fraction of collisions with total kinetic energy greater than Ea increases. 
E) the activation energy increases.

Question 20

The thermal decomposition of acetaldehyde, CH3CHO F1F1F1S1F1F1F10 CH4 + CO, is a second-order reaction. The following data were obtained at 518°C.   Calculate the rate constant for the decomposition of acetaldehyde from the above data.

Accepted Answer

A) 2.2 F1F1F1S1F1F1F10 10-3/s 
B) 0.70 mmHg/s 
C) 2.2 F1F1F1S1F1F1F10 10-3/mmHg·s 
D) 6.7 F1F1F1S1F1F1F10 10-6/mmHg·s 
E) 5.2 F1F1F1S1F1F1F10 10-5/mmHg·s 
A) 2.2 F1F1F1S1F1F1F10 10-3/s 
B) 0.70 mmHg/s 
C) 2.2 F1F1F1S1F1F1F10 10-3/mmHg·s 
D) 6.7 F1F1F1S1F1F1F10 10-6/mmHg·s 
E) 5.2 F1F1F1S1F1F1F10 10-5/mmHg·s

Exam 13: Chemical Kinetics

A certain reaction A  products is second order in A. If this reaction is 85% complete in 12 minutes, how long would it take for the reaction to be 15% complete?

When acetaldehyde at a pressure of 364 mmHg is introduced into an evacuated 500.mL flask at 518°C, the half-life for the second-order decomposition process, CH3CHO  CH4 + CO, is 410.s.What will the total pressure in the flask be after 1.00 hour?

Nitric oxide reacts with chlorine to form nitrosyl chloride, NOCl. Use the following data to determine the rate equation for the reaction. NO + 1/2Cl2  NOCl

Use the table of data shown below to calculate the average rate of the reaction AB between 10 s and 20 s.

The reaction A + 2B  products has been found to have the rate law, rate = k[A] [B]2. While holding the concentration of A constant, the concentration of B is increased from x to 3x. Predict by what factor the rate of reaction increases.

The reaction C4H10  C2H6 + C2H4 has an activation energy (Ea)of 350 kJ/mol, and the Ea of the reverse reaction is 260 kJ/mol. Estimate H, in kJ/mol, for the reaction as written above.

At 25°C the rate constant for the first-order decomposition of a pesticide solution is 6.40  10-3 min-1. If the starting concentration of pesticide is 0.0314 M, what concentration will remain after 62.0 min at 25°C?

For the reaction BrO3- + 5Br-+ 6H+ →\rarr→ 3Br2 + 3H2O at a particular time, - Δ\DeltaΔ [BrO3-]/ Δ\DeltaΔ t = 1.5 * 10-2 M/s. What is - Δ\DeltaΔ [Br-]/ Δ\DeltaΔ t at the same instant?

The following reaction in aqueous solution was found to be first order in [OH-], first order in [C2H5Br], and inverse first order in Br-. C2H5Br + OH-  C2H5OH + Br- Which one of the following mechanisms is consistent with the observed reaction order?

Use the following data to determine the rate law for the reaction shown below. 2NO + H2  N2O + H2O

The reaction A + 2B  products was found to follow the rate law: rate = k[A]2[B].Predict by what factor the rate of reaction will increase when the concentration of A is doubled, the concentration of B is tripled, and the temperature remains constant.

At a particular temperature the first-order gas-phase reaction 2N2O5  2N2O4 + O2 has a half-life for the disappearance of dinitrogen pentoxide of 3240 s. If 1.00 atm of N2O5 is introduced into an evacuated 5.00 L flask, what will be the total pressure of the gases in the flask after 1.50 hours?

The rate law predicted by the following two-step mechanism is rate = k[A][B].

For the hypothetical reaction A + 3B  2C, the rate should be expressed as

A rate constant with the units L2 mol-2 s-1 is consistent with a

For the chemical reaction system described by the diagram below, which statement is true? If the Ea for the forward reaction is 25 kJ/mol and the enthalpy of reaction is -95 kJ/mol, what is Ea for the reverse reaction?

For the following reaction, Δ\DeltaΔ P(C6H14)/ Δ\DeltaΔ t was found to be -6.2 *10-3 atm/s. C6H14(g) →\rarr→ C6H6(g)+ 4H2(g) Determine Δ\DeltaΔ P(H2)/ Δ\DeltaΔ t for this reaction at the same time.

Which one of the following changes would alter the rate constant (k)for the reaction 2A + B  products?

An increase in the temperature of the reactants causes an increase in the rate of reaction. The best explanation for this behavior is that as the temperature increases,

The thermal decomposition of acetaldehyde, CH3CHO  CH4 + CO, is a second-order reaction. The following data were obtained at 518°C. Calculate the rate constant for the decomposition of acetaldehyde from the above data.

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When acetaldehyde at a pressure of 364 mmHg is introduced into an evacuated 500.mL flask at 518°C, the half-life for the second-order decomposition process, CH₃CHO  CH₄ + CO, is 410.s.What will the total pressure in the flask be after 1.00 hour?

Nitric oxide reacts with chlorine to form nitrosyl chloride, NOCl. Use the following data to determine the rate equation for the reaction. NO + ¹/₂Cl₂  NOCl

The reaction A + 2B  products has been found to have the rate law, rate = k[A] [B]². While holding the concentration of A constant, the concentration of B is increased from x to 3x. Predict by what factor the rate of reaction increases.

The reaction C₄H₁₀  C₂H₆ + C₂H₄ has an activation energy (E_a)of 350 kJ/mol, and the E_a of the reverse reaction is 260 kJ/mol. Estimate H, in kJ/mol, for the reaction as written above.

At 25°C the rate constant for the first-order decomposition of a pesticide solution is 6.40  10^-3 min^-1. If the starting concentration of pesticide is 0.0314 M, what concentration will remain after 62.0 min at 25°C?

For the reaction BrO₃^-+ 5Br^-+ 6H⁺ $\rarr$ 3Br₂ + 3H₂O at a particular time, - $\Delta$ [BrO₃^-]/ $\Delta$ t = 1.5 * 10^-2 M/s. What is - $\Delta$ [Br^-]/ $\Delta$ t at the same instant?

The following reaction in aqueous solution was found to be first order in [OH^-], first order in [C₂H₅Br], and inverse first order in Br^-. C₂H₅Br + OH^-  C₂H₅OH + Br^- Which one of the following mechanisms is consistent with the observed reaction order?

Use the following data to determine the rate law for the reaction shown below. 2NO + H₂  N₂O + H₂O

The reaction A + 2B  products was found to follow the rate law: rate = k[A]²[B].Predict by what factor the rate of reaction will increase when the concentration of A is doubled, the concentration of B is tripled, and the temperature remains constant.

A rate constant with the units L² mol^-2 s^-1 is consistent with a

For the chemical reaction system described by the diagram below, which statement is true? If the E_a for the forward reaction is 25 kJ/mol and the enthalpy of reaction is -95 kJ/mol, what is E_a for the reverse reaction?

For the following reaction, $\Delta$ P(C₆H₁₄)/ $\Delta$ t was found to be -6.2 *10^-3 atm/s. C₆H₁₄(g) $\rarr$ C₆H₆(g)+ 4H₂(g) Determine $\Delta$ P(H₂)/ $\Delta$ t for this reaction at the same time.

The thermal decomposition of acetaldehyde, CH₃CHO  CH₄ + CO, is a second-order reaction. The following data were obtained at 518°C. Calculate the rate constant for the decomposition of acetaldehyde from the above data.