Cambridge - Chemical Equilibrium

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Date:
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Cambridge - Chemical Equilibrium
Multiple Choice
Identify the choice that best completes the statement or answers the question
NOTE: These questions were taken from an American textbook, so many of the vocabulary terms may be
unfamiliar & noticeably absent from your British textbook. If in doubt, you should make every attempt to
Google or otherwise lookup the terms to compare with your textbook. This will be a learning process. In
fact this “quiz” is actually supposed to help you learn more than check to see what you have already
learned.
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1. At equilibrium,
a. all reactions have ceased.
b. only the forward reaction continues.
c. only the reverse reaction continues.
d. both the forward and reverse reactions continue.
2. At equilibrium,
a. the forward reaction rate is lower than the reverse reaction rate.
b. the forward reaction rate is higher than the reverse reaction rate.
c. the forward reaction rate is equal to the reverse reaction rate.
d. no reactions take place.
3. At equilibrium, the total amount of the product(s)
a. is always equal to the total amount of the reactants.
b. is always greater than the total amount of the reactants.
c. is always less than the total amount of the reactants.
d. may be equal to, greater than, or less than the total amount of the reactants.
4. The value of the equilibrium constant for a reaction
a. changes with concentration.
c. changes with temperature.
b. changes with time.
d. is the same under all conditions.
5. How does the value of K show that a reaction reaches equilibrium very quickly?
a. K is large.
b. K is small.
c. K is zero.
d. The value of K does not show how quickly a reaction comes to equilibrium.
6. A very low value of K indicates that
a. equilibrium is reached slowly.
c. reactants are favored.
b. products are favored.
d. equilibrium has been reached.
7. A very high value of K indicates that
a. equilibrium is reached slowly.
c. reactants are favored.
b. products are favored.
d. equilibrium has been reached.
8. A value of K near 1 indicates that at equilibrium probably
a. only products are present.
b. only reactants are present.
c. significant quantities of both products and reactants are present.
d. the reactions occur at a moderate rate.
9. The equilibrium constant depends on changes in
a. pressure.
b. concentrations.
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c. temperature.
d. pressure, concentrations, and temperature.
____ 10. In the equation
, what represents the concentrations of the reactants?
a. [Y] and [Z]
c.
b. [W] and [X]
d.
____ 11. In the equation
, what represents the concentrations of the products?
a. [Y] and [Z]
c.
b. [W] and [X]
d.
____ 12. How do coefficients from a chemical equilibrium appear when the chemical equilibrium
expression is written?
a. as coefficients
c. as subscripts
b. as exponents
d. They do not appear.
____ 13. What is the chemical equilibrium expression for the equation
2A2B + 3CD
a.
b.
A4D + C3B2?
c.
d.
____ 14. An equilibrium mixture of SO2, O2, and SO3 gases at 1500 K is determined to consist of 0.344
mol/L SO2, 0.172 mol/L O2, and 0.56 mol/L SO3. What is the equilibrium constant for the
system at this temperature? The balanced equation for this reaction is
2SO2(g) + O2(g)
2SO3(g).
a. 0.41
c. 6.7
b. 2.8
d. 0.15
____ 15. If the system 2CO(g) + O2(g)
2CO2(g) has come to equilibrium and then more CO(g) is
added,
a. [CO2] increases and [O2] decreases.
c. [CO2] decreases and [O2] decreases.
b. [CO2] increases and [O2] increases.
d. both [CO2] and [O2] remain the same.
____ 16. If the pressure on the equilibrium system 2CO(g) + O2(g)
2CO2(g) is increased,
a. the quantity of CO(g) increases.
b. the quantity of CO2(g) decreases.
c. the quantity of CO2(g) increases.
d. the quantities in the system do not change.
____ 17. If the pressure on the equilibrium system N2(g) + O2(g)
2NO(g) decreases,
a. the quantity of N2(g) decreases.
b. the quantity of NO(g) increases.
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c. the quantity of NO(g) decreases.
d. the quantities in the system do not change.
If the temperature of the equilibrium system CH3OH(g) + 101 kJ
CO(g) + 2H2(g) increases,
a. [CH3OH] increases and [CO] decreases.
b. [CH3OH] decreases and [CO] increases.
c. [CH3OH] increases and [CO] increases.
d. the concentrations in the system do not change.
Reactions tend to run to completion if
a. a gaseous product forms and escapes.
b. a product in the same phase as the reactants forms.
c. one product is highly ionized.
d. one product is highly soluble.
To what degree does water ionize?
a. completely
c. slightly
b. to a large extent
d. not at all
Acids make litmus paper turn
a. red.
c. blue.
b. yellow.
d. black.
Acids react with
a. bases to produce salts and water.
c. water to produce bases and salts.
b. salts to produce bases and water.
d. neither bases, salts, nor water.
A substance that ionizes nearly completely in aqueous solutions and produces H3O+ is a
a. weak base.
c. weak acid.
b. strong base.
d. strong acid.
Which of the following is NOT a strong acid?
a. HNO3
c. H2SO4
b. CH3COOH
d. HCl
A Brønsted-Lowry acid is
a. an electron-pair acceptor.
c. a proton acceptor.
b. an electron-pair donor.
d. a proton donor.
+
In the equation HCl(g) + H2O(l) H3O (aq) + Cl–(aq), which species is a Brønsted-Lowry
acid?
a. HCl
c. Cl–
b. H2O
d. none of the above
In the reaction HF + H2O
H3O+ + F–, a conjugate acid-base pair is
a. HF and H2O.
c. H3O+ and H2O.
b. F– and H3O+.
d. HF and H3O+.
+
–
In the reaction HClO3 + NH3
NH4 + ClO3 , the conjugate acid of NH3 is
a. HClO3.
c. NH4+.
b. ClO3–.
d. not shown.
+
What is the concentration of H3O in pure water?
a. 10–7 M
c. 55.4 M
b. 0.7 M
d. 107 M
The pH of an acidic solution is
a. less than 0.
c. greater than 7.
b. less than 7.
d. greater than 14.
Name:__________________________________________________________
Date:
Cambridge - Chemical Equilibrium
Answer Section
MULTIPLE CHOICE
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