Name: 
 

Ch 18 Test Section 3,4 and 5



Matching (Value 5)
 
 
Match each item with the correct statement below.
a.
spontaneous reaction
d.
reaction mechanism
b.
entropy
e.
elementary reaction
c.
chemical equilibrium
 

 1. 

when the forward and reverse reactions take place at the same rate
 

 2. 

a reaction that releases free energy
 

 3. 

the measure of disorder
 

 4. 

Reactants are converted to products in a single step.
 

 5. 

includes all elementary reactions of a complex reaction
 

Multiple Choice (Value 25)
Identify the choice that best completes the statement or answers the question.
 

 6. 

The energy that is available to do work in a reaction is called ____.
a.
heat
c.
entropy
b.
enthalpy
d.
free energy
 

 7. 

Entropy measures ____.
a.
energy
c.
disorder
b.
heat transferred
d.
force
 

 8. 

Which physical state of nitrogen has the highest entropy?
a.
solid
c.
gas
b.
liquid
d.
vapor
 

 9. 

The amount of disorder in a system is measured by its ____.
a.
activation energy
c.
equilibrium position
b.
entropy
d.
Kmc009-1.jpg
 

 10. 

Which one of the following systems has the highest entropy?
a.
10 mL of water at 10mc010-1.jpgC
b.
10 mL of water at 50mc010-2.jpgC
c.
10 mL of water at 100mc010-3.jpgC
d.
All have the same entropy because all are water.
 

 11. 

If a system is left to change spontaneously, in what state will it end?
a.
the same state in which it began
b.
the state with lowest possible energy
c.
the state with the maximum disorder
d.
the state with the lowest possible energy consistent with the state of maximum disorder
 

 12. 

Which reaction results in the greatest increase in entropy?
a.
A ® B
c.
2A ® B
b.
A ® 2B
d.
3A ® B
 

 13. 

In which of these systems is the entropy decreasing?
a.
air escaping from a tire
c.
salt dissolving in water
b.
snow melting
d.
a liquid cooling
 

 14. 

Which of the following statements explains why the melting of ice is a spontaneous reaction at room temperature and pressure?
a.
Melting is accompanied by a decrease of entropy.
b.
Melting is accompanied by an increase of entropy.
c.
Melting is accompanied by a decrease of energy.
d.
Melting is accompanied by an increase of energy.
 

 15. 

The two factors that determine whether a reaction is spontaneous or nonspontaneous are ____.
a.
entropy and disorder
b.
entropy and energy
c.
electron configuration and ionic charge
d.
energy and heat of reaction
 

 16. 

Which of the following statements is true?
a.
All spontaneous processes are exothermic.
b.
All nonspontaneous processes are endothermic.
c.
All spontaneous processes release free energy.
d.
Entropy always increases in a spontaneous process.
 

 17. 

Spontaneous reactions ____.
a.
are always exothermic
b.
always take place at a rapid rate
c.
always result in increased disorder of the system
d.
always release free energy
 

 18. 

The melting of ice at temperatures above 0mc018-1.jpgC ____.
a.
liberates heat
c.
is not favorable
b.
is not spontaneous
d.
is endothermic
 

 19. 

Which of the following is true about the combustion of carbon?
a.
The reaction is spontaneous.
b.
Carbon is produced from oxygen and carbon dioxide.
c.
Enthalpy remains constant.
d.
Entropy decreases.
 

 20. 

What determines whether or not a reaction is spontaneous?
a.
change in molar volume and heat change
b.
change in enthalpy only
c.
enthalpy change and entropy change
d.
change in entropy only
 

 21. 

Which of the following is true about the numerical value of Gibbs free-energy change for a spontaneous reaction?
a.
It is not related to enthalpy.
b.
It is negative.
c.
It indicates that work must be expended.
d.
It is positive for temperatures above 850mc021-1.jpgC.
 

 22. 

Which variable is NOT required to calculate the Gibbs free-energy change for a chemical reaction?
a.
change in enthalpy
c.
temperature in kelvins
b.
temperature in mc022-1.jpgC
d.
change in entropy
 

 23. 

What is the rate law for the following reaction?
A + 2B ® C + D
a.
rate = k[A][B]
c.
rate = k[A][B]mc023-2.jpg
b.
rate = k[A]mc023-1.jpg[B]
d.
rate = k[A]mc023-3.jpg[B]mc023-4.jpg
 

 24. 

What is the order of the following reaction? A + 2B ® C + D
a.
zero
c.
second
b.
first
d.
third
 

 25. 

In a first-order reaction, how does the rate change if the concentration of the reactant decreases to one-third its original value?
a.
The rate decreases by a factor of one-ninth.
b.
The rate decreases by a factor of one-third.
c.
The rate decreases by a factor of one-half.
d.
The rate stays the same.
 

 26. 

If a reaction rate decreases by a factor of one-ninth when a reactant concentration is decreased by one-third, what is the order of the reaction with respect to that reactant?
a.
fourth
c.
second
b.
third
d.
first
 

 27. 

When nitrous oxide is converted to nitrogen and oxygen, what is the term used to describe the oxygen atoms formed?
a.
reactants
c.
activated complexes
b.
products
d.
intermediates
 

 28. 

An elementary reaction ____.
a.
has only elements as reactants
b.
has only elements as products
c.
never needs a catalyst
d.
converts reactants to products in a single step
 

 29. 

For a complex reaction, the reaction progress curve ____.
a.
is a flat line
c.
has several hills and valleys
b.
has only one peak
d.
shows energy versus pressure
 

 30. 

What information is NOT given by an overall equation for a chemical reaction?
a.
the relative numbers of molecules used
b.
the probable order of the reaction
c.
the number of atoms participating in the reaction
d.
the reaction mechanism
 

Short Answer
 

 31. 

Calculate the concentration of a silver ion when the solubility product constant of AgI is 10sa031-1.jpg.
 

 32. 

What is the approximate concentration of aluminum ions if the solubility product constant of Al(OH)sa032-1.jpg is 27 sa032-2.jpg 10sa032-3.jpg?
 

 33. 

The solubility product constant of calcium hydroxide is 6.5 sa033-1.jpg 10sa033-2.jpg. If 0.10 mol of sodium hydroxide is added to 1 L of 0.0010M Ca(OH)sa033-3.jpg, what is the final concentration of the calcium ion?
 

 34. 

In a first-order reaction, what is the rate constant if the rate is 0.050M/s and the reactant concentration is 0.030M?
 

 35. 

What is the rate of a first-order reaction that has a reactant concentration of 1.1M and a rate constant of 0.14/s?
 

 36. 

In a first-order reaction, what is the reactant concentration if the rate constant is 0.2/s and the rate is 0.004M/s?
 

 37. 

What is the rate of a first-order reaction that has a reactant concentration of 0.1M and a rate constant of 0.1/s?
 

 38. 

In a first-order reaction, what is the reactant concentration if the rate constant is 0.1/s and the rate is 0.001M/s?
 

 39. 

In a first-order reaction, what is the rate constant if the rate is 0.01M/s and the reactant concentration is 0.01M?
 

 40. 

The rate law for the following reaction is: Rate = k[A]sa040-1.jpg[B]sa040-2.jpg.
aA + bB sa040-3.jpg cC + dD
From the following data, find the kinetic order of the reaction with respect to A and B, as well as the overall order.

Initial Concentration      Initial Concentration      Initial Rate
of A(mol/L)            of B(mol/L)            (mol/L sa040-4.jpg s)
0.05                  0.05                  2 sa040-5.jpg 10sa040-6.jpg
0.10                  0.05                  4 sa040-7.jpg 10sa040-8.jpg
0.20                  0.05                  8 sa040-9.jpg 10sa040-10.jpg
0.01                  0.05                  0.4 sa040-11.jpg 10sa040-12.jpg
0.01                  0.10                  3.2 sa040-13.jpg 10sa040-14.jpg
0.01                  0.20                  25.6 sa040-15.jpg 10sa040-16.jpg
 

 41. 

In a two-step reaction mechanism, how many elementary reactions occur?
 



 
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