Chem 120 Exam Sample

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CHEM 120 (Fall 2011) 1.

Test #1 (Version 001)

Page 2 of 8

(0.5 marks) Elemental mercury, Hg(l), has a density of 13.6 g mL−1 at 25°C. What is the volume of 4.25 grams of Hg(l)? A. B. C. D. E. 0.313 mL 3.20 mL 17.8 mL 57.8 mL none of the above

2.

(0.5 marks) What is the mass of 0.45 mol S? Choose the closest value. A. B. C. D. E. 9.7 g 0.45 g 14 g 0.049 g 15 g

3.

(0.5 marks) Balance the following equation using the smallest whole number coefficients. C5H10O5 + O2 → H2O + CO2 What is the coefficient of O2 ? A. B. C. D. E. 2 3 5 6 none of the above

4.

(0.5 marks) Sulfurous acid, H2SO3, is A. B. C. a strong electrolyte a weak electrolyte a nonelectrolyte

CHEM 120 (Fall 2011) 5.

Test #1 (Version 001)

Page 3 of 8

(0.5 marks) What is the oxidation state of C in C2H5OH? A. B. C. D. E. −3 +6 +2 −4 −2

6.

(0.5 marks) Which of the following combinations of solutions yields a precipitate? A. B. C. D. E. KNO3(aq) and CaCl2(aq) AgNO3(aq) and NH4Br(aq) Mg(NO3)2(aq) and Li2SO4(aq) More than one of these combinations yields a precipitate. None of these combinations yields a precipitate.

7.

(0.5 marks) Is the reaction below a precipitation, an acid-base or an oxidation-reduction reaction? Assume the reaction occurs in aqueous solution. CuSO4 + Zn → Cu + ZnSO4 A. B. C. a precipitation reaction an acid-base reaction an oxidation-reduction reaction

8.

(0.5 marks) What is the percentage by mass of oxygen in UO2? Molar masses (in g mol−1) A. B. C. D. 33% 12% 6.7% 67% U, 238.0 O, 16.00

CHEM 120 (Fall 2011) 9.

Test #1 (Version 001)

Page 4 of 8

(1 mark) What is the net ionic equation for the reaction that occurs when aqueous solutions of hypochlorous acid, HClO, and magnesium hydroxide, Mg(OH)2, are combined? A. B. C. D. E. 2 HClO(aq) + Mg(OH)2(aq) → Mg(ClO)2(aq) + 2 H2O(l) H+(aq) + OH−(aq) → H2O(l) 2 HClO(aq) + Mg2+(aq) + 2 OH−(aq) → Mg(ClO)2(aq) + 2 H2O(l) HClO(aq) + OH−(aq) → ClO−(aq) + H2O(l) 2 H+(aq) + 2 ClO−(aq)...
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