Question 1

The half life for the decay of radium is 1620 years.What is the rate constant for this first-order process?

Accepted Answer

A)  4.28 × 10-4 yr-1 
B)  1.12 × 10-4 yr-1 
C)  2.33 × 10-4 yr-1 
D)  8.91 × 10-4 yr-1 
E)  6.17 × 10-4 yr-1 
A)  4.28 × 10-4 yr-1 
B)  1.12 × 10-4 yr-1 
C)  2.33 × 10-4 yr-1 
D)  8.91 × 10-4 yr-1 
E)  6.17 × 10-4 yr-1

Question 2

A sample contains 1.46 g of Cobalt-55.After 2.00 days,0.219 g remains.What is the half-life?

Accepted Answer

A)  17.5 h-1 
B)  22.6 h-1 
C)  1.35 h-1 
D)  0.540 h-1 
E)  11.6 h-1 
A)  17.5 h-1 
B)  22.6 h-1 
C)  1.35 h-1 
D)  0.540 h-1 
E)  11.6 h-1

Question 3

Reaction rate can change with

Accepted Answer

A)  temperature. 
B)  the addition of a catalyst. 
C)  reactant concentrations. 
D)  A and C. 
E)  A, B, and C. 
A)  temperature. 
B)  the addition of a catalyst. 
C)  reactant concentrations. 
D)  A and C. 
E)  A, B, and C.

Question 4

What data should be plotted to show that experimental concentration data fits a zeroth-order reaction?

Accepted Answer

A)  ln[reactant] vs. time 
B)  1/[reactant] vs. time 
C)  ln(k) vs. 1/T 
D)  ln(k) vs. Ea 
E)  [reactant] vs. time 
A)  ln[reactant] vs. time 
B)  1/[reactant] vs. time 
C)  ln(k) vs. 1/T 
D)  ln(k) vs. Ea 
E)  [reactant] vs. time

Question 5

Given the following proposed mechanism,predict the rate law for the overall reaction. 2NO2 + Cl2 → 2NO2Cl (overall reaction)
Mechanism
NO2 + Cl2 → NO2Cl + Cl slow
NO2 + Cl → NO2Cl fast

Accepted Answer

A)  Rate = k[NO2][Cl2] 
B)  Rate = k[NO2]2[Cl2]2 
C)  Rate = k[NO2][Cl] 
D)  Rate = k[NO2Cl][Cl]2 
E)  Rate = k[NO2Cl]2 
A)  Rate = k[NO2][Cl2] 
B)  Rate = k[NO2]2[Cl2]2 
C)  Rate = k[NO2][Cl] 
D)  Rate = k[NO2Cl][Cl]2 
E)  Rate = k[NO2Cl]2

Question 6

Which of the following statements is TRUE?

Accepted Answer

A)  The rate constant does not depend on the activation energy for a reaction where the products are lower in energy than the reactants. 
B)  A catalyst raises the activation energy of a reaction. 
C)  Rate constants are temperature dependent. 
D)  The addition of a homogeneous catalyst does not change the activation energy of a given reaction. 
E)  None of the above are true. 
A)  The rate constant does not depend on the activation energy for a reaction where the products are lower in energy than the reactants. 
B)  A catalyst raises the activation energy of a reaction. 
C)  Rate constants are temperature dependent. 
D)  The addition of a homogeneous catalyst does not change the activation energy of a given reaction. 
E)  None of the above are true.

Question 7

Identify the methods used to monitor a reaction as it occurs in the reaction flask.

Accepted Answer

A)  polarimeter 
B)  spectrometer 
C)  pressure measurement 
D)  all of the above 
E)  none of the above 
A)  polarimeter 
B)  spectrometer 
C)  pressure measurement 
D)  all of the above 
E)  none of the above

Question 8

The half-life for the second-order decomposition of HI is 15.4 s when the initial concentration of HI is 0.67 M.What is the rate constant for this reaction?

Accepted Answer

A)  1.0 × 10-2 M-1s-1 
B)  4.5 × 10-2 M-1s-1 
C)  9.7 × 10-2 M-1s-1 
D)  2.2 × 10-2 M-1s-1 
E)  3.8 × 10-2 M-1s-1 
A)  1.0 × 10-2 M-1s-1 
B)  4.5 × 10-2 M-1s-1 
C)  9.7 × 10-2 M-1s-1 
D)  2.2 × 10-2 M-1s-1 
E)  3.8 × 10-2 M-1s-1

Question 9

Given the following balanced equation,determine the rate of reaction with respect to [N2]. N2(g)+ 3 H2(g)→ 2 NH3(g)

Accepted Answer

A)  Rate = +   
B)  Rate = -   
C)  Rate = +     
D)  Rate = -     
E)  It is not possible to determine without more information. 
A)  Rate = +   
B)  Rate = -   
C)  Rate = +     
D)  Rate = -     
E)  It is not possible to determine without more information.

Question 10

A radioactive isotope decays with a half life of 645 s.How much of the material remains after 2.00 minutes?

Accepted Answer

A)  12.1% 
B)  87.9% 
C)  0.02% 
D)  99.8% 
A)  12.1% 
B)  87.9% 
C)  0.02% 
D)  99.8%

Question 11

Given the following balanced equation,determine the rate of reaction with respect to [Cl2].If the rate of Cl2 loss is 4.24 × 10-2 M/s,what is the rate of formation of NOCl?
2 NO(g)+ Cl2(g)→ 2 NOCl(g)

Accepted Answer

A)  4.24 × 10-2 M/s 
B)  2.12 × 10-2 M/s 
C)  1.06 × 10-1 M/s 
D)  8.48 × 10-2 M/s 
E)  1.61 × 10-2 M/s 
A)  4.24 × 10-2 M/s 
B)  2.12 × 10-2 M/s 
C)  1.06 × 10-1 M/s 
D)  8.48 × 10-2 M/s 
E)  1.61 × 10-2 M/s

Question 12

A reaction is followed and found to have a rate constant of 3.36 × 104 M-1s-1 at 344 K and a rate constant of 7.69 M-1s-1 at 219 K.Determine the activation energy for this reaction.

Accepted Answer

A)  23.8 kJ/mol 
B)  42.0 kJ/mol 
C)  11.5 kJ/mol 
D)  12.5 kJ/mol 
E)  58.2 kJ/mol 
A)  23.8 kJ/mol 
B)  42.0 kJ/mol 
C)  11.5 kJ/mol 
D)  12.5 kJ/mol 
E)  58.2 kJ/mol

Question 13

Derive an expression for a "1/3-life" for a first-order reaction.

Accepted Answer

A)    
B)    
C)    
D)    
E)    
A)    
B)    
C)    
D)    
E)

Question 14

If the activation energy for a given compound is found to be 103 kJ/mol,with a frequency factor of 4.0 × 1013 s-1,what is the rate constant for this reaction at 398 K?

Accepted Answer

A)  1.2 s-1 
B)  8.2 s-1 
C)  3.9 × 1010 s-1 
D)  1.7 × 1010 s-1 
E)  2.5 × 107 s-1 
A)  1.2 s-1 
B)  8.2 s-1 
C)  3.9 × 1010 s-1 
D)  1.7 × 1010 s-1 
E)  2.5 × 107 s-1

Question 15

Which of the following represents the integrated rate law for a zeroth-order reaction?

Accepted Answer

A)    = - kt 
B)    -   = kt 
C)  [A]t - [A]o = - kt 
D)  k = Ae(-Ea/RT) 
E)    =     + lnA 
A)    = - kt 
B)    -   = kt 
C)  [A]t - [A]o = - kt 
D)  k = Ae(-Ea/RT) 
E)    =     + lnA

Question 16

Carbon-14,which is present in all living tissue,radioactively decays via a first-order process.A one-gram sample of wood taken from a living tree gives a rate for carbon-14 decay of 13.6 counts per minute.If the half-life for carbon-14 is 5720 years,how old is a wood sample that gives a rate for carbon-14 decay of 11.9 counts per minute?

Accepted Answer

A)  5.3 × 102 yr 
B)  7.6 × 102 yr 
C)  1.1 × 103 yr 
D)  9.4 × 103 yr 
A)  5.3 × 102 yr 
B)  7.6 × 102 yr 
C)  1.1 × 103 yr 
D)  9.4 × 103 yr

Question 17

The decomposition of     in solution in carbon tetrachloride proceeds via the reaction 2     (soln)→   (soln)+   (soln)
The reaction is first order and has a rate constant of 4.82 ×     at 64°C.If the reaction is initiated with 0.058 mol in a 1.00-L vessel,how many moles remain after 151 s?

Accepted Answer

A)  0.055 M 
B)  0.060 M 
C)  0.028 M 
D)  12 M 
E)  2.0 ×   M 
A)  0.055 M 
B)  0.060 M 
C)  0.028 M 
D)  12 M 
E)  2.0 ×   M

Question 18

Given the following balanced equation,determine the rate of reaction with respect to [NH3]. N2(g)+ 3 H2(g)→ 2 NH3(g)

Accepted Answer

A)  Rate = +   
B)  Rate = -   
C)  Rate = +     
D)  Rate = -     
E)  It is not possible to determine without more information. 
A)  Rate = +   
B)  Rate = -   
C)  Rate = +     
D)  Rate = -     
E)  It is not possible to determine without more information.

Question 19

What is the difference between average reaction rate and instantaneous reaction rate?

Accepted Answer

An average reaction rate is determined u

Question 20

Define half-life.

Accepted Answer

A half-life of a reaction is t

Exam 15: Chemical Kinetics

The half life for the decay of radium is 1620 years.What is the rate constant for this first-order process?

A sample contains 1.46 g of Cobalt-55.After 2.00 days,0.219 g remains.What is the half-life?

Reaction rate can change with

What data should be plotted to show that experimental concentration data fits a zeroth-order reaction?

Given the following proposed mechanism,predict the rate law for the overall reaction. 2NO2 + Cl2 → 2NO2Cl (overall reaction) Mechanism NO2 + Cl2 → NO2Cl + Cl slow NO2 + Cl → NO2Cl fast

Which of the following statements is TRUE?

Identify the methods used to monitor a reaction as it occurs in the reaction flask.

The half-life for the second-order decomposition of HI is 15.4 s when the initial concentration of HI is 0.67 M.What is the rate constant for this reaction?

Given the following balanced equation,determine the rate of reaction with respect to [N2]. N2(g)+ 3 H2(g)→ 2 NH3(g)

A radioactive isotope decays with a half life of 645 s.How much of the material remains after 2.00 minutes?

Given the following balanced equation,determine the rate of reaction with respect to [Cl2].If the rate of Cl2 loss is 4.24 × 10-2 M/s,what is the rate of formation of NOCl? 2 NO(g)+ Cl2(g)→ 2 NOCl(g)

A reaction is followed and found to have a rate constant of 3.36 × 104 M-1s-1 at 344 K and a rate constant of 7.69 M-1s-1 at 219 K.Determine the activation energy for this reaction.

Derive an expression for a "1/3-life" for a first-order reaction.

If the activation energy for a given compound is found to be 103 kJ/mol,with a frequency factor of 4.0 × 1013 s-1,what is the rate constant for this reaction at 398 K?

Which of the following represents the integrated rate law for a zeroth-order reaction?

The decomposition of in solution in carbon tetrachloride proceeds via the reaction 2 (soln)→ (soln)+ (soln) The reaction is first order and has a rate constant of 4.82 × at 64°C.If the reaction is initiated with 0.058 mol in a 1.00-L vessel,how many moles remain after 151 s?

Given the following balanced equation,determine the rate of reaction with respect to [NH3]. N2(g)+ 3 H2(g)→ 2 NH3(g)

What is the difference between average reaction rate and instantaneous reaction rate?

Define half-life.

Essentials: Units, Measurements, and Problem Solving

Atoms

The Quantum Mechanical Model of the Atom

Periodic Properties of the Elements

Molecules and Compounds

Chemical Bonding I

Chemical Bonding Ii

Chemical Reactions and Chemical Quantities

Introduction to Solutions and Aqueous Reactions

Thermochemistry

Gases

Liquids, Solids, and Intermolecular Forces

Crystalline Solids and Modern Materials

Solutions

Chemical Equilibrium

Acids and Bases

Aqueous Ionic Equilibrium

Free Energy and Thermodynamics

Electrochemistry

Radioactivity and Nuclear Chemistry

Organic Chemistry

Transition Metals and Coordination Compounds

Filters

Given the following proposed mechanism,predict the rate law for the overall reaction. 2NO₂ + Cl₂ → 2NO₂Cl (overall reaction) Mechanism NO₂ + Cl₂ → NO₂Cl + Cl slow NO₂ + Cl → NO₂Cl fast

Given the following balanced equation,determine the rate of reaction with respect to [N₂]. N₂(g)+ 3 H₂(g)→ 2 NH₃(g)

Given the following balanced equation,determine the rate of reaction with respect to [Cl₂].If the rate of Cl₂ loss is 4.24 × 10^-2 M/s,what is the rate of formation of NOCl? 2 NO(g)+ Cl₂(g)→ 2 NOCl(g)

A reaction is followed and found to have a rate constant of 3.36 × 10⁴ M^-1s^-1 at 344 K and a rate constant of 7.69 M^-1s^-1 at 219 K.Determine the activation energy for this reaction.

If the activation energy for a given compound is found to be 103 kJ/mol,with a frequency factor of 4.0 × 10¹³ s^-1,what is the rate constant for this reaction at 398 K?

Given the following balanced equation,determine the rate of reaction with respect to [NH₃]. N₂(g)+ 3 H₂(g)→ 2 NH₃(g)