AP Chemistry Name :
Worksheet : Ch 4-2 Date :
A. Multiple Choice – No calculators may be used on the multiple choice.
_____ 1. How many moles of sodium are there in 50.0 mL of a 0.20 M solution of sodium phosphate?
a. 0.010 mol b. 0.020 mol c.0 .030 mol d. 0.040 mol e. .050 mol
_____ 2. How many grams of calcium nitrate (164.10 g/mol) are needed to make a 100.0 mL of a 0.50 M solution of calcium nitrate?
a. 41. grams b. 4.1 grams c. 82. grams d. 8.2 grams e. .041 grams
_____ 3. A mixture is formed by adding 20.0 mL of 0.20 M potassium carbonate with 30.0 mL of a 0.50 M solution of potassium chloride. What is the resulting concentration of potassium ions?
a. 0.38 M b. 0.76 M c. 0.46 M d. 0.92 M e. 0.23 M
_____ 4. 20.0 mL of a 0.25 M solution of silver acetate is added to 20.0 mL of a 1.0 M solution of potassium iodide. What is the resulting concentration of silver ions in solution?
a. 0.13 M b. 0.25 M c. 0.025 M d. 0.10 M e. negligible
_____ 5. When 100.0 mL of 0.50 M lithium carbonate are added to 100.0 mL of 0.50 M aluminum nitrate a precipitate forms. What is the correct order of ions in solution from the largest to the smallest concentration?
a. [Li+] > [CO32-] > [Al3+] > [NO3-]
b. [Li+] > [Al3+] > [CO32-] > [NO3-]
c. [Al3+] > [CO32-] > [Li+] > [NO3-]
d. [NO3-] > [Li+] > [Al3+] > [CO32-]
e. [NO3-] > [Li+] > [CO32-] > [Al3+]
_____ 6. A 30.0 mL sample of 0.20 M sodium carbonate is added to a 40.0 mL sample of 0.20 M calcium nitrate. After the reaction occurs, what is the resulting concentration of calcium ions?
a. 0.033 M b. 0.025 M c. 2.5 M d. 0.055 M e. 0.029 M
_____ 7. When a hydrate of copper(II) chloride (MW of CuCl2 = 136.45 g) is heated, it loses 21% of its mass. What is the formula of its hydrate?
a. CuCl2·H2O b. CuCl2·2H2O c. CuCl2·3H2O d. CuCl2·4H2O e. CuCl2·5H2O
_____ 8. If 47.6 grams of magnesium chloride (MW = 95.21 g) is dissolved in enough water to form 500. mL of solution, what are the resulting molarities of the magnesium and chloride ions?
a. [Mg2+] = 0.25 M, [Cl-] = 0.50 M d. [Mg2+] = 1.5 M, [Cl-] = 1.5 M
b. [Mg2+] = 0.50 M, [Cl-] = 1.0 M e. [Mg2+] = 1.5 M, [Cl-] = 3.0 M
c. [Mg2+] = 1.0 M, [Cl-] = 2.0 M
From the list at the right, which of the following ions must be absent if :
_____ 9. The solution is colorless.
_____ 10. The solution does not effervesce when hydrochloric acid is added..
_____ 11. No precipitate forms with a solution of potassium chloride.
_____ 12. No precipitate forms when a dilute solution of sulfuric acid is added.
_____ 13. No odor can be detected when the solution is added to warm sodium hydroxide.
14. Assign oxidation states for all atoms in each of the following compounds.
a. KMnO4
b. NiO2
c. K4Fe(CN)6 (Fe only)
d. (NH4)2HPO4
e. P4O6
f. Fe3O4
g. XeOF4
h. SF4
i. CO
j. Na2C2O4
15. Assign the oxidation state for chlorine in each of the following anions:
a. OCl-
b. C1O2-
c. C1O3-
d. C1O4-
16. Assign the oxidation state for nitrogen in each of the following.
a. Li3N
b. NH3
c. N2H4
d. NO
e. N2O
f. NO2
g. NO2-
h. NO3-
i. N2
17. Specify which of the following are oxidation-reduction reactions, and identify the oxidizing agent, the reducing agent, the substance being oxidized, and the substance being reduced.
a. CH4(g) + 2O2(g) à CO2(g) + 2H2O(g)
b. Zn(s) + 2HCl(aq) à ZnCl2(aq) + H2(g)
c. Cr2O72-(aq) + 2OH-(aq) à 2CrO42-(aq) + H2O(/)
d. O3(g) + NO(s) à O2(g) + NO2(g)
e. 2H2O2(/) à 2H2O(l) + O2(g)
f. 2CuCl(aq) à CuCl2(aq) + Cu(s)
18. Specify which of the following are oxidation-reduction reactions, and identify the oxidizing agent, the reducing agent, the substance being oxidized, and the substance being reduced.
a. Cu(s) + 2Ag+(aq) à 2Ag(s) + Cu2+(aq)
b. HCl(g) + NH3(g) à NH4C1(s)
c. SiCl4(l) + 2H2O(l) à 4HCl(aq) + SiO2(s)
d. SiCl4(/) + 2Mg(s) à 2MgCl2(s) + Si(s)
e. Al(OH)4-(aq) à AlO2-(aq) + 2H2O(/)
19. Balance the following oxidation-reduction reactions that occur in acidic solution.
a. Zn(s) + H+(aq) à Zn2+(aq) + H2(g)
b. I- (aq) + ClO- (aq) à l3-(aq) + Cl-(aq)
c. As2O3(s) + NO3-(aq) à H3AsO4(aq) + NO(g)
d. Br- (aq) + MnO4- (aq) à Br2(/) + Mn2+(aq)
e. CH3OH(aq) + Cr2O72- (aq) à CH2O(aq) + Cr3+ (aq)
20. Balance the following oxidation-reduction reactions that occur in basic solution.
a. Al(s) + MnO4- (aq) à MnO2(s) + Al(OH)4- (aq)
b. Cl2(g) à Cl- (aq) + OCl- (aq)
c. NO2- (aq) + Al(s) à NH3(g) + AlO2- (aq)
d. Cr(s) + CrO42- (aq) à Cr(OH)3(s)
e. MnO4-(aq) + S2-(aq) à MnS(s) + S(s)
Answers : 14a K = +1, Mn = +7, O = -2 14d. N = -3, H = +1, P = +5. O = -2 14f. Fe = +8/3 O = -2 14j. Na = +1, C = +3, O = -2 15b. Cl = +3 16a. N = -3 16c. N= -2 16g N = +3 17a. CH4 (C) is oxidized (red. ag.), O2 (O) is reduced (ox. ag) 17d. NO (N) is ox. (red. ag.) and O3 (O) is reduced(ox. ag.) 18b. Not a redox reaction 18d. Mg is ox. (red. ag.), SiCl4 (Si) is reduced (ox. ag.)
19a.Zn(s) + 2 H+(aq) à Zn2+ (aq) + H2(g)
19b. 3 I- + 2H+ + ClO- à I3- + Cl- + H2O
19c. 7 H2O + 4 H+ + 3 As2O3 + 4 NO3- -à 4 NO + 6 H3AsO4
19d. 16H+ + 2 MnO4- + 10 Br- à 5 Br2 + 2 Mn2+ + 8 H2O
19e. 8H+ + 3 CH3OH + Cr2O72- à 2 Cr3+ + 7 H2O + 3 CH2O
20a. 2 H2O + Al + MnO4- à Al(OH)4- + MnO2
20b. 4 OH- + 2Cl2 à 2 Cl- + 2 ClO- + 2 H2O
20c. OH- + H2O + NO2- + 2 Al à NH3 + 2 AlO2-
20d. 4 H2O + Cr + CrO42- à 2Cr(OH)3 + 2OH-
20e. 8 H2O + 7 S2- + 2 MnO4- à 5 S + 2 MnS + 16 OH-