Chemistry 12

Name: _______________________________

Solutions and Electrochemistry Test Section I: Fill in the Blanks—Use the solubility curve to answer the questions below on the sheet provided [10] 1. How many grams of solute are required to saturate 100 g of water in each solution below? [2] a. KCl at 80ºC b. SO2 at 20 ºC 2. State whether each solution described below is saturated, unsaturated or supersaturated when mixed with 100 g of water. [2] a.

40 g of NaCl at 50ºC

b.

80 g of KNO3 at 60ºC

3. How many grams of KNO3 per 100 g of water would be crystallized from a saturated solution as the temperature drops from: [2] a.

70ºC to 20ºC

b.

50ºC to 30ºC

4. How many additional grams of NaNO3 are required to keep the NaNO3 solution saturated during the temperature changes of 10ºC to 30ºC? [1] 5. At what temperature are the solutes below equally soluble in 100g of water? [2] a. NaNO3 and KNO3 b. SO2 and KClO3 6. Which solute is least affected by the temperature changes? [1]

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Chemistry 12

Name: _______________________________

Section II: Matching—place the letter representing the correct term for each description on the sheet provided [10 marks]

1. ____ A characteristic of a molecular solid. 2. ____ Solution that contains more solute than a saturated solution at the same temperature. 3. ____ A solution of two metals. 4. ____ is the maximum quantity of a substance that will dissolve in a given amount of solvent at a given temperature. 5. ____ Is cancelled out in an ionic equation; does not participate directly in a reaction. 6. ____ is the process of decreasing the concentration of a solution, usually by adding more solvent. 7. ____ A homogeneous mixture of dissolved substances containing a solvent and a solute. 8. ____ is the opposite of dissolving 9. ____ A homogeneous mixture with relative large amount of solute compared with the volume of solvent. 10. ____Consists of positive and negative ions, held together by charge attractions.

Word Bank: A. B. C. D.

Alloy Crystallization Dilute Solution Concentrated Solution

E. F. G. H.

Ionic Solid Dilution Dissociation Unsaturated

I. J. K. L.

Molecular Solid Non-electrolyte Spectator Ion Electronegative

M. N. O. P.

Saturated Solubility Solution Supersaturated

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Chemistry 12

Name: _______________________________

Section III: Multiple Choice Questions—place your answers on the sheet provided [20] 1. In a redox reaction which best describes what happens to the reducing agent? a. b. c. d.

Forms a negative ion Forms a positive ion Gains electrons Loses electrons

2. Which type of reaction is not a redox reaction? a. b. c. d.

Double displacement Composition Decomposition Single displacement

3. What is the oxidation number of S in MgS2O6? a. b. c. d.

+3 +5 +6 +7

4. What is true in the reaction below? Ga3+(aq) + Rb(s)  a. b. c. d.

Rb3+(aq) + Ga(s)

Ga loses electrons Ga3+ is an oxidizing agent Rb gains electrons Rb3+ is a reducing agent

5. Which species is oxidized in the reaction below? 5 Ag + MnO4- + 8H+  5 Ag+ + Mn2+ + 4 H2O a. b. c. d.

Ag H Mn O

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Chemistry 12

Name: _______________________________

6. Which describes oxidation? a. Gain of electrons b. Gain of protons c. Loss of electrons d. Loss of protons 7. What is the oxidation number of O in O2 (g)? a. b. c. d.

-2 0 +1 +2

8. Which species is reduced in the reaction below? Zn(s) + CuSO4(aq)  ZnSO4(aq) + Cu(s) a. b. c. d.

Zn (s) Zn2+ (aq) Cu (s) Cu2+ (aq)

9. What is the oxidation half-reaction for the electrochemical cell below? Ni│ Ni2+││ Cd2+│ Cd a. b. c. d.

Cd  Cd2+ + 2 eCd2+ + 2 e-  Cd Ni  Ni2+ + 2 eNi2+ + 2 e-  Ni

10. What is the cell voltage, Eo, for the electrochemical cell formed from the half-reactions below? Fe2+(aq) + 2 e-  Fe(s) Hg (l)  Hg2+(aq) + 2ea. b. c. d.

-1.30 V -0.40 V +0.40 V +1.30 V

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Chemistry 12

Name: _______________________________

11. Which would balance the reaction below? X-  X2a. b. c. d.

Add one electron to the product side Add one electron to the reactant side Add two electrons to the product side Add two electrons to the reactant side

12. Which describes the reaction below? Ni (s) + Pb2+ (aq)  Ni2+ (aq) + Pb (s) Eo (V) -0.13 -0.13 0.13 0.13

a. b. c. d.

Spontaneity Non-spontaneous Spontaneous Non-spontaneous Spontaneous

13. Which equals the sum of all oxidation numbers in a polyatomic ion? a. b. c. d.

Overall charge of the ion Oxidation number of the central atom Total number of atoms Total number of valence electrons

14. What is the oxidation number of Cr in CrO42-? a. -2 b. +4 c. +6 d. +8 15. Which is the reducing agent in the reaction below? Cl2 + 2 Br-  2 Cl- + Br2 a. b. c. d.

BrBr2 ClCl2

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Chemistry 12

Name: _______________________________

16. Which is a redox reaction? a. b. c. d.

2 NaCl + Pb(NO3)2  PbCl2 + 2 NaNO3 2 Ag + Cu(NO3)2  Cu + 2 AgNO3 2 NO2  N2O4 N2O3 + H2O  2 HNO2

17. When a solid zinc strip was placed in a blue solution of Cu2+(aq) , the solution turned colourless. What happened to the Cu2+ (aq)? a. b. c. d.

Decomposed Dissolved Oxidized Reduced

18. What is the Eo for the overall reaction below? 3 Co + 2 Au3+  3 Co2+ + 2 Au a. b. c. d.

1.22 V 1.78 V 2.16 V 3.84 V

19. If the half reaction below is balanced in acidic solution, how many moles of hydrogen ions are required to balance the overall equation? Ti  TiO22a. b. c. d.

1 2 3 4

20. Which species can be both an oxidizing agent and reducing agent? (Hint: look at the periodic table) a. b. c. d.

Co3+ (aq) Co (s) Sn2+ (aq) Sn (s)

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Chemistry 12

Name: _______________________________

Section IV—Extended Responses—show ALL your workings in the space provided [20] 1. i) Draw a diagram of the cell represented by Cr(s)│Cr2+(aq) │KCl(aq)│Pb2+(aq) │Pb(s). Label the following: anode, cathode, direction of electron flow, direction of ion flow, and the salt bridge. [4]

ii) Provide the two half reactions and overall balanced redox reaction. [2]

iii) What is Eo for this cell? Is it spontaneous or non-spontaneous? [2]

2. What is the percent concentration (m/v) of 450.0 mL of a solution that contains 50.0g of strontium fluoride, SrF2? [2]

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Chemistry 12

Name: _______________________________

3. Under basic conditions, balance the half-reaction below: [4] Ag+ (aq) + S2O32- (aq)  SO42- (aq) + Ag(s)

4. Write non-ionic, total ionic and net ionic equations for the reactions below: Barium reacts with a magnesium sulfate solution. [3]

Nonionic: Total ionic: Net ionic: 5. Determine the concentration of aqueous magnesium and aqueous acetate ions in a 0.75 M solution of magnesium acetate. [3]

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Chemistry 12

Name: _______________________________ ANSWER SHEET

Section I: Fill in the Blanks [10] 1. a. ___________

b. ___________

2. a. ___________

b. ___________

3. a. ___________

b. ___________

4.

___________

5. a. ___________ 6.

b. ___________

___________

Section II: Matching [10] 1. _____________

6. _____________

2. _____________

7. _____________

3. _____________

8. _____________

4. _____________

9. _____________

5. _____________

10. _____________

Section III: Multiple Choices [20] 1. _____________

11. _____________

2. _____________

12. _____________

3. _____________

13. _____________

4. _____________

14. _____________

5. _____________

15. _____________

6. _____________

16. _____________

7. _____________

17. _____________

8. _____________

18. _____________

9. _____________

19. _____________

10. _____________

20. _____________

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