+1 862 207 3288 Modified True/False
Indicate whether the sentence or statement is true or false. If false, change the identified word or phrase to make the sentence or
statement true.
____ 1. When a precipitate forms at the bottom of a container after 2 unsaturated solutions are mixed, the solid precipitate is
always in equilibrium with its liberated ions in solution. _________________________
____ 2. Ksp values are temperature dependent. _________________________
____ 3. More potassium bromide can dissolve in distilled water than in a solution of potassium chloride.
_________________________
____ 4. The formula for silver acetate is AgC3H5O2. _________________________
____ 5. The Ksp equilibrium expression for lead(II) chloride is Pb2Cl(s) <====> 2Pb2+(aq) + Cl1-(aq). _________________________
____ 6. For the gaseous equilibrium shown, 3A + B <====> C + 2D, some C is added to the system. The quantity of D will rise.
_________________________
____ 7. For the gaseous equilibrium shown, 2A + 3B <====> C + 2D + heat.
If the temperature of the system is decreased, the quantity of B will increase 3/2 as much as the quantity of A.
______________________________
____ 8. For the gaseous equilibrium shown, 3A + B <====> 4C + D + heat.
If some B is removed from the system, the quantity of C will decrease 4’s as much as the quantity of D decreases.
_________________________
____ 9. For the gaseous equilibrium shown, 2A + 3B <====> 4C + D + heat.
If some B is added to the system, the quantity of C will decrease 4’s as much as the quantity of D decreases.
______________________________
____ 10. In a saturated solution of cobalt(II) hydroxide, the quantity of cobalt(II) ion is double the quantity of hydroxide
ion. __________________________________________________
____ 11. A system at equilibrium means the concentration of reactants is equal to the concentration of products.
_______________________________________________________
____ 12. The pH scale ranges from 0 to 14. ___________________________________
____ 13. A concentrated weak acid cannot have a lower pH than a dilute strong acid. _________________________
____ 14. A concentrated weak base can have a lower pOH than a dilute strong base. _________________________
____ 15. 1.0 mol/L solutions of weak bases will have a higher pH than 1.0 mol/L solutions of strong bases.
_________________________
____ 16. Conjugate acid base partners differ by a single proton. _________________________
____ 17. Salts containing anion which is not found in a strong acid can act like weak bases. _________________________
____ 18. Salts contain cations found in the alkali metal family cannot act like weak acids. _________________________
____ 19. If the pH of an aquatic solution at 95oC is 4.5 the pOH must be 9.5. ___________________________________
____ 20. When HCl is titrated with NaOH the endpoint is indicated when an excess of HCl turns the indicator a different colour.
_________________________
Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
____ 21. In a saturated solution of aluminum hydroxide, the concentration of aluminum ion is 2.4 10-8 mol/L. The Ksp of
aluminum hydroxide would be which of the following?
a. 1.7 10-15 d. 9.0 10-30
b. 4.2 10-23 e. none of the above
c. 1.0 10-30
____ 22. For the equilibrium system below, which of the following would result in an increase in the quantity of Cl2(g)?
PCl3(g) + Cl2(g) <=====> PCl5(g) + 45 kJ
a. adding some PCl3(g) d. increasing the volume of the container
b. removing some PCl5(g) e. injecting some He gas
c. decreasing temperature
____ 23. The Ksp for a substance A2B is 1.2 10-12. The [B] must be which of the following?
a. 4.0 10-11 d. 1.3 10-4
b. 3.6 10-12 e. 2.6 10-4
c. 6.7 10-5
____ 24. The Ksp for a substance A2B is 1.2 10-12. The [A] must be which of the following?
a. 4.0 10-11 d. 1.3 10-4
b. 3.6 10-12 e. none of the above
c. 6.7 10-5
____ 25. The Ksp for a substance AB3 is 7.8 10-10. The [A] is which of the following?
a. 7.0 10-3 d. 1.6 10-2
b. 5.3 10-3 e. 2.9 10-11
c. 2.3 10-3
____ 26. Which of the following salts act like acids when applied to the soil?
a. BeCl2 d. NaF
b. KF e. KCl
c. FeI3
____ 27. Which of the following salts act like bases when applied to the soil?
a. NaHSO4 d. LiNO3
b. KNO2 e. KClO4
c. CaCl2
____ 28. When water is heated to its boiling point the system has which of the following?
a. increased entropy and decreased enthalpy
b. decreased entropy and increased enthalpy
c. increased both entropy and enthalpy
d. decreased both entropy and enthalpy
e. none of the above
____ 29. When water is cooled to its freezing point the system has which of the following?
a. increased entropy and decreased enthalpy
b. decreased entropy and increased enthalpy
c. increased both entropy and enthalpy
d. decreased both entropy and enthalpy
e. none of the above
____ 30. A solution of nitrous acid has a pH of 2.45. The [H1+] in mol/L and pOH must be respectively
a. 3.5 10-3, 11.55 d. 2.8 10-12, 12
b. 3.6 10-3, 11.55 e. 3.8 10-3, 12.55
c. 2.8 10-12, 11.6
Completion
Complete each sentence or statement.
31. If solutions of sodium phosphate and zinc bromide were mixed and a precipitate formed, the precipitate would be
_________________________.
32. 4NO(g) 2N2O(g) + O2(g); during this chemical change the algebraic sign for the entropy change is predicted to be
____________________.
33. A buffer can contain a weak base and a salt containing _____________________________________________.
34. A 1.5 mol/L solution of HCl(aq) has a pH of ____________________.
35. The pOH of a basic solution is always ____________________.
Matching
Here is a list of weak acids. Match to its conjugate base partner below. If no match exists indicate by writing none.
a. H2O d. HPO42-
b. HSO41- e. H2CO3
c. HC2H3O2 f. H2C6H6O6
____ 36. C2H3O21-
____ 37. SO42-
____ 38. HC6H6O61-
____ 39. OH1-
____ 40. HCO31-
Short Answer
41. Consider the equilibrium below:
If 1.5 mol of PCl5 was placed in a 1.0 L container and allowed to reach equilibrium, what would the value of Ke be if at equilibrium
[PCl5] = 1.2 mol/L?
PCl3(g) + Cl2(g) <=====> PCl5(g)
42. Consider the equilibrium below:
If 1.2 mol of H2 and 1.2 mol of O2 was placed in a 1.0 L container and allowed to reach equilibrium, what would the value of Ke be if
at equilibrium [HI] = 0.40 mol/L?
H2(g) + I2(g) <=====> 2HI(g)
43. Consider the equilibrium below:
If 1.6 mol of HI was placed in a 1.0 L container and allowed to reach equilibrium, what would the equilibrium concentrations be for H2
(g), I2(g) and HI(g) if the Ke = 36?
H2(g) + I2(g) <=====> 2HI(g)
44. If the pH of an acid solution at 25oC is 6.18, what is the pOH; and the [H1+], [OH1-] in mol/L?
45. If the [H1+] of a solution at 25oC is 4.9 10-4 mol/L, calculate the [OH1-] in mol/L, the pH and the pOH.
Problem
46. If 12 L of a saturated solution of PbSO4 is found to contain 0.46 g of PbSO4, what is the Ksp of PbSO4
47. What mass of Mg(OH)2 would be found in 7.6 102 mL of a saturated solution of Mg(OH)2 if the Ksp of Mg(OH)2 is 9.0
10-12?
48. If 145 mL of a 0.0078 mol/L solution of CuNO3 was mixed with 195 mL of a 1.48 10-3 mol/L solution of KI, would a
precipitate form? Calculate the ion product for the potential precipitate. The Ksp of CuI is 1 10-12.
49. What is the pH of a 3.4 mol/L solution of KOH?
50. 24 mL of 0.39 mol/L acetic acid is titrated with a standardized 0.33 mol/L KOH solution. Calculate the pH of the
solution after 17 mL of the KOH solution has been added. Assume the Ka of acetic acid is 1.8 10-5.
Chemistry 12 Unit 4 Test
Modified True/False
Indicate whether the sentence or statement is true or false. If false, change the identified word or phrase to make the sentence or
statement true.
____ 1. Oxidation processes always result in a decrease in the oxidation number of a species. _________________________
____ 2. Silver is a stronger reducing agent than aluminum. _________________________
____ 3. An oxidizing agent is an electron donor. ______________________________
____ 4. When an atom loses an electron during a redox reaction, its oxidation number increases. _________________________
____ 5. When the oxidation number of an atom decreases during a redox reaction, it is acting as a reducing agent.
_________________________
____ 6. The oxidation number of a monatomic ion is the same as the charge on the ion. _________________________
____ 7. In all redox reactions, electrons are transferred from an oxidizing agent to a reducing agent.
________________________________________
____ 8. In redox reactions, metals always behave as reducing agents. _________________________
____ 9. In a redox table, the strongest oxidizing agent is at the top left side of the table. _________________________
____ 10. In a redox table, the strongest reducing agent is at the bottom left side of the table. ______________________________
____ 11. The strongest oxidizing agent present in an electric cell always undergoes a reduction at the cathode.
_________________________
____ 12. The electrolytic cell potential, , is always positive. _________________________
____ 13. The anode of an electrolytic cell is the positive electrode. _________________________
____ 14. Electrolysis is the process by which electrical energy is passed through a molten ionic compound to cause a
nonspontaneous reaction to occur. _________________________
____ 15. To produce one mole of copper by the electrolysis of requires the same amount of electric charge as the production of
one mole of silver from . ____________________________________
____ 16. The electrolysis of water produces twice as much volume of hydrogen gas at the cathode as oxygen gas at the anode.
_________________________
____ 17. The electrolysis of water using inert electrodes produces hydrogen gas at the anode and oxygen gas at the cathode.
___________________________________________________
____ 18. Electrolysis is used in electroplating, and in refining of metals. _________________________
____ 19. When water is electrolyzed, the products, and , possess less potential energy than the reactant, .
________________________________
____ 20. In a silver-plating cell, the object to be plated is made the anode. _________________________
Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
____ 21. In which of the following compounds does nitrogen have the highest oxidation number?
a. d.
b. e.
c.
____ 22. Experiments were performed with four strips of metals , , , and , and their corresponding nitrate solutions , ,
, and . The following observations were obtained:
A
no reaction no reaction no reaction no reaction
precipitate no reaction precipitate precipitate
precipitate no reaction no reaction no reaction
precipitate no reaction precipitate no reaction
Which of the following is the correct list of the metal ions in order of decreasing strength as oxidizing agents (strongest oxidizing
agent first)?
a. d.
b. e.
c.
____ 23. Which element is oxidized in the following reaction?
a. in d. in
b. in e.
c. in
____ 24. Given the following unbalanced oxidation-reduction equation:
In the balanced equation, the coefficient of is
a. 2 d. 5
b. 3 e. 6
c. 4
____ 25. Consider the above cell at 25 C.
In the left half-cell, a lead electrode is in contact with 0.10 mol/L and in the right half-cell, a copper electrode is in contact
with 0.20 mol/L . The standard reduction potentials are as follows:
Which of the following statements about this cell is false?
a. ions migrate into the left half-cell through the salt bridge
b. electrons flow from the copper electrode to the lead electrode
c. the cell is not at standard conditions
d. ions migrate into the right half-cell through the salt bridge
e. reduction occurs at the copper electrode
____ 26. Given
The for the reaction
is
a. +0.18 V d. +0.37 V
b. 0.18 V e. 0.37 V
c. 0.67 V
____ 27. The concentration of both solutions in the cell below are 1.0 mol/L.
Given the following standard reduction potentials:
Which of the following statements are true?
I. oxidation occurs at the Ag electrode.
II. the Ag electrode is the negative terminal of the cell.
III. electrons flow from the Ni electrode to the Ag electrode through the external circuit.
IV. the Ni electrode is the anode.
a. I and II d. III and IV
b. I and III e. II and IV
c. II and III
____ 28. Given the standard reduction potentials for the following half-reactions:
What is the standard reduction potential for the reaction
?
a. +1.16 V d. +0.58 V
b. +0.10 V e. 0.58 V
c. 0.10 V
____ 29. Given the following information:
What is the minimum voltage necessary for the electrolysis of a 1.0 mol/L solution of sodium sulfate using inert electrodes?
a. 4.72 V d. 2.83 V
b. 3.53 V e. 1.23 V
c. 3.12 V
____ 30. In an electrolytic cell using inert electrodes, a current of 4.00 A is passed through a molten binary salt with the
formula for 20.0 minutes. 1.15 g of metal is produced at the cathode. What is the metal ?
a. d.
b. e.
c.
Completion
Complete each sentence or statement.
31. A reaction in which electrons are gained is a(n) ____________________ reaction.
32. If the algebraic sum of the for two half-cells is ____________________, the reaction will proceed spontaneously.
33. Negatively charged ions are called ____________________ and migrate toward the ____________________ electrode of the
electrochemical cell.
34. In an electrochemical cell oxidation occurs at the ____________________.
35. When an atom gains an electron, it is acting as a(n) ____________________ agent.
36. When an atom gains an electron during a redox reaction, its oxidation number ____________________.
37. Downs cell is used for the production of ____________________ metal.
38. The quantity of charge transferred by a current of 1.0 A during a time of 1.0 s is called a(n) ____________________.
39. One faraday is equal to one ____________________ of electrons.
40. In the electrolysis of copper sulfate solution, ____________________ are reduced at the cathode.
Matching
Match each of the following terms with its appropriate description.
a. electrode e. primary cell
b. electrolyte f. electric cell
c. secondary cell g. fuel cell
d. battery h. corrosion
____ 41. an electric cell that cannot be recharged
____ 42. an electric cell that can be recharged
____ 43. the spontaneous oxidation of a metal by substances in the environment
____ 44. a group of two or more electric cell connected in series
____ 45. an aqueous electrical conductor
Short Answer
46. List four factors that accelerate the corrosion of iron.
47. What process occurs at the cathode of an electrolytic cell while the cell is operating?
48. Predict the cathode and anode reactions during the electrolysis of 1 mol/L nickel iodide solution, , using carbon
electrodes.
49. Predict the net cell reaction during the electrolysis of 1 mol/L nickel iodide solution, , using carbon electrodes.
50. Predict the net cell reaction during the electrolysis of 1 mol/L sodium hydroxide solution, , using inert electrodes.
