Chemistry quiz
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Practice Problems -- Set #4 (chap 9 and 10)
1. MgCl2 is a(an)
(A). acid (B). base (C). salt (D). covalent compound
2. Which one of the compounds is insoluble in water (hint: solubility rules)
(A). BaSO4 (B). NaCl (C). KI (D). HCl (E). All of the above are soluble in water.
3. Identify a strong base.
(A). HNO3 (B). KCl (C). NH4OH (D). NaOH (E). Na2SO4
4. Acid-base reaction is a neutralization reaction. If 12.50 mL of 1.20 M NaOH solution is used to
neutralize 45.25 mL of HNO3 solution, calculate the concentration of the original HNO3
solution.
(A). 0.231 M (B). 0.995 M (C). 0.887 M (D). 0.331 M (E). 9.90 M
5. Acid-base reaction is a neutralization reaction. If 12.50 mL of 1.20 M NaOH solution is used to
neutralize 45.25 mL of H2SO4 solution, calculate the concentration of the original H2SO4
solution.
2NaOH + H2SO4 Na2SO4 + 2H2O (balanced?)
(A). 0.231 M (B). 0.995 M (C). 0.887 M (D). 0.166 M (E). 0.331 M
6. Oxidation-reduction (redox) reactions involve electrons. If an element in ground state loses two
electrons during the redox reaction, this process is called oxidation.
(A). True (B). False
7. What is the oxidation number of P in H3PO4?
(A). +3 (B). +5 (C). -3 (D). -5 (E). 0
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8. What is the oxidation number of P in PO4 3-
?
(A). +3 (B). +5 (C). -3 (D). -5 (E). 0
9. Which of the following molecule is an electrolyte?
(A). Pure water (B). Sugar solution (C). Pure butanol (D). KCl solution (E). More than two answer is given
10. Milk of magnesia contains magnesium hydroxide. What mass of Mg(OH)2 is needed to prepare
500.00 mL of 0.0500 M solution of magnesium hydroxide?
(A). 0.987 g of Mg(OH)2 (B). 0.654 g of Mg(OH)2 (C). 1.46 g of Mg(OH)2 (D). 10.7 g of Mg(OH)2 (E). No correct answer is given
11. What element is oxidized in the following reaction? 2Li + O2 Li2O
(A). Li (B). O2 (C). More than one correct answer is given (D). No correct answer is given
12. Identify /predict the products of the reaction between Na2SO4 and BaCl2 solutions. (double
replacement! solubility rules!)
Na2SO4(aq) + BaCl2(aq) ? + ?
13. Write the complete molecular equation for the reaction between Na2SO4 and BaCl2 solutions.
14. Write the complete ionic equation for the reaction between Na2SO4 and BaCl2 solutions.
15. Write the net ionic equation for the reaction between Na2SO4 and BaCl2 solutions.
16. Identify the driving force(s) in the reaction between Na2SO4 and BaCl2 solutions.
17. In the following reaction, how many grams of sodium sulfate are needed to react with 3.08
moles of strontium nitrate? (hint: stoichiometry Na2SO4: Sr(NO3)2 = 1:1)
Sr(NO3)2 (aq) + Na2SO4 (aq) SrSO4 (s) + 2 NaNO3 (aq) (balanced) (A). 437 g Na2SO4 (B). 2.09 g Na2SO4 (C). 1.11 g Na2SO4 (D). 6.16 g Na2SO4 (E). 1.54 g Na2SO4
18. Name HClO4.
(A). Hydrochloric acid (B). Perchloric acid (C). Chloric acid
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(D). Chlorous acid (E). Perchloric acid
19. Strong electrolytes are,
(A). Always salts (B). Always acids (C). Always bases (D). Always ionic compounds (E). No correct answer is given
20. Which of the following is the net ionic equation for
Pb(NO3)2 (aq) + 2NaI(aq) 2NaNO3(aq) + PbI2 (s) ? (Balanced?)
(A). Pb(NO3)2 (aq) + 2NaI(aq) 2NaNO3(aq) + PbI2 (B). Pb2+ (aq) + 2 I
- (aq) PbI2 (s)
(C). Pb2+ (aq) + 2 I - (aq) 2 PbI2
(D). NO3- (aq) + Na + (aq) NaNO3(aq)
(E). No correct answer is given.
21. What is the driving force in the reaction HCl (aq) + NaOH (aq) NaCl (aq) + H2O(l) ?
(A). Formation of an insoluble salt (B). Formation of a gas (C). Formation of a nonelectrolyte (D). There is no driving force. This reaction will not occur.
22. PbI2 cannot be used as an electrolyte.
(A). True (B). False
23. How much energy is needed to warm 25.0 g of benzene from 1.00 o C to 8.00
o C? (Your
textbook and “CRC Handbook of Chemistry and Physics” would be great sources to look for
Cs, benzene)
(A). 265 J (B). 89.0 J (C). 65.7 J (D). 23.0 J (E). 1.22 J
24. The production of 1.000 g of C2H2 gas from graphite and H2 gas requires 8.7033 kJ under
standard conditions. What is the H o f(C2H2)?
2 C(graphite) + H2 (g) C2H2 (g)
(A). 226.6 kJ/mol (B). 113.3 kJ/mol (C). 10.00 kJ/mol (D). 9.962 kJ/mol (E). 1.244 kJ/mol
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25. How much energy will warm 10.0 g of gold, if the T = 4.1 o C? (Your textbook and “CRC
Handbook of Chemistry and Physics” would be great sources to look for Cs, gold)
(A). 0.128 J (B). 4.18 J (C). 5.25 J (D). 10.0 J (E). 41.0 J
26. How many joules need to be added to 4.50 g of graphite to raise its temperature by 25 K?
(A). 25 J (B). 4.5 J (C). 8.8 J (D). 1.9 J (E). 81 J
27. What is the heat of reaction for the reaction 2 Fe(s) + O3 (g) Fe2O3?
(A). -7.450 kJ/mol (B). -966.9 kJ/mol (C). -7.888 kJ/mol (D). +1.333 kJ/mol (E). +142.7 kJ/mol
28. What is the specific heat of a material if 45.0 J are needed to warm a 2.25 g sample from 0.0 o C
to 22.0 o C?
(A). 0.909 J/g oC (B). 0.450 J/g oC (C). 0.225 J/g oC (D). 2.20 J/g oC (E). No correct answer is given.
29. Thermal energy is a form of chemical energy. (A). True (B). False
30. An open system is one that can gain (or lose) matter and energy.
(A). True (B). False
31. How much heat (in kJ) is transferred from surroundings to warm 100.0 g of water from 5.0 o C
to 22.0 o C?
(A). 7.11 kJ (B). 10.0 kJ (C). 5.00 kJ (D). 2.20 kJ (E). No correct answer is given.
32. A 5.5 g block of Cu at 95.0 o C is placed in 100.0 mL of water at 22.5
o C. What is the final
temperature of the water? (hint: This problem involves transfer of heat energy.) (D= 1.00 g/mL)
(A). 90.0 oC (B). 23.5 oC (C). 22.9 oC (D). 93.8 oC (E). 94.7 oC
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33. What is the H o reaction for 2SO2(g) + O2 (g) 2SO3 (g)
(H o
f SO3 (g) = -395.7 kJ/mol; H o
f SO2 (g) = -296.8 kJ/mol; H o
f O2 (g) = 0 kJ/mol)
(A). -275.3 kJ/mol (B). 9.965 kJ/mol (C). -197.8 kJ/mol (D). -247.9 kJ/mol (E). -5.568 kJ/mol
34. Which one is true based on the following reaction:
CH4(g) + 2O2(g) CO2(g) + 2H2O(g) ∆H°rxn = -802.3 kJ
(A). This is an endothermic reaction (B). This is an exothermic reaction (C). The products have more potential energy (D). The reactants have more potential energy (E). More than one correct answer is given
35. In exothermic reactions, the products of the reaction have more potential energy than the
reactants. (A). True (B). False
36. Which of the following signs on q and w represent a system that is doing work on the
surroundings, as well as gaining heat from the surroundings?
(A). q = +, w = - (B). q = -, w = + (C). q = +, w = + (D). q = -, w = -
37. Use the ΔH°f and ΔH°rxn information provided to calculate ΔH°f for HCl(g)
CH4(g) + 4Cl2(g) CCl4(g) + 4HCl(g) ΔH°rxn = -389 kJ
ΔH°f (kJ/mol)
CH4(g) -75
CCl4(g) -96
(A). -389 kJ/mol
(B). -92 kJ/mol
(C). +113 kJ/mol
(D). -71 kJ/mol
(E). +79 kJ/mol
38. Calculate the change internal energy (ΔE) for a system that is giving off 45.0 kJ of heat and is
performing 895 J of work on the surroundings.
(A). 64.1 kJ
(B). -64.1 kJ
(C). -45.9 kJ
(D). +99.9 kJ
(E). -90.5 kJ
38. Heat capacity: The quantity of heat required to change a system's temperature by 1 o C
(A). True (B). False
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39. Specific heat capacity: The quantity of heat required to raise the temperature of 1 gram of a
substance by 1 o C (Hint: consider analyzing the units of Cs)
(A). True (B). False
40. A 4.00 g sample of water at 22.5 o C is heated by the addition of 98.0 J of energy. The final
temperature of the water is _____ o C. (The specific heat capacity of water is 4.18 J/g.
o C.)
(A). 28.4 oC (B). -14.3 oC (C). 45.7 oC (D). -76.7 oC (E). No correct answer is given.
41. When 0.500 g of cyclohexane, C6H12, is combusted in a bomb calorimeter that has a water
sheath containing 750.0 g of water, the temperature of the water increased by 5.5 °C. Assuming
that the specific heat of water is 4.18 J/(g °C), and that the heat absorption by the calorimeter is
negligible, calculate the enthalpy of combustion per mole of cyclohexane.
(A). 2.90 x 106 J/mol (B). 4.20 x 106 J/mol (C). 1.19 x 104 J/mol (D). 2.97 x 105 J/mol (E). 8.21 x 106 J/mol
42. Choose the reaction that illustrates ΔH°f for Ca(NO3)2.
(A). Ca(s) + N2(g) + 3O2(g) Ca(NO3)2 (s)
(B). Ca +
(aq) + NO3 - (aq) Ca(NO3)2 (s)
(C). Ca +
(s) + NO3(aq) Ca(NO3)2 (s)
(D). Ca(s) + N2(g) + O2(g) Ca(NO3)2 (s)
(E). 2Ca(s) + 2N2(g) + 3O2(g) Ca(NO3)2 (s)
43. Identify a green-house gas
(A). O3 (g) (B). C2H4(g) (C). CO2 (g) (D). H2O(g) (E). More than one correct answer is given
44. The temperature and pressure for the standard state for a liquid are 298 K and 1 atm.
(A). True (B). False
45. Give the equation with the elements in Na2SO4 in their standard state as the reactants and
Na2SO4 as the product.
(A). 2 Na(s) + 1/8 S8 (s, rhombic) + 2 O2(g) Na2SO4 (B). Na(s) + S8 (s, rhombic) + 2 O2(g) Na2SO4 (C). Na(s) + S (s, rhombic) + ½ O2(g) NaSO (D). Na(s) + 1/8 S8 (s, rhombic) + 2O2(g) NaSO4
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46. A gas cylinder contains 10.0 kg of C3H8 (propane) gas. Calculate the heat associated with the
complete combustion of all of the propane in the cylinder. MW of C3H8 is 44.10 g/mol.
C3H8(g) + 5O2(g) 3CO2(g) + 4H2O(g) ∆Hrxn = -2044 kJ
(A). -5.68 x 105 kJ (B). -4.63 x 105 kJ (C). +5.68 x 105 kJ (D). +4.63 x 105 kJ (E). 2.31 x 105 kJ
47. Which statement is FALSE?
(A) An exothermic reaction gives heat off to the surroundings.
(B) Enthalpy is the sum of a system's internal energy and the product of pressure and volume.
(C) ΔErxn is a measure of heat.
(D) ΔHrxn is the heat of reaction.
(E) Endothermic has a positive ΔH.
48. Use the ΔH o f information provided to calculate ΔH
o rxn for the following reaction:
SO2Cl2(g) + 2H2O(l) 2HCl(g) + H2SO4(l) ΔH o rxn = ?
ΔH o f (kJ/mol)
SO2Cl2(g) -364
H2O(l) -286
HCl(g) -92
H2SO4(l) -814
49. Calculate the change in internal energy (ΔE) for a system that is giving off 26.0 kJ of heat and is
changing from 12.00 L to 6.00 L in volume at 1.50 atm pressure. (101.3 J = 1 L∙atm)
50. Use bond energies to calculate the ∆Hrxn for the following reaction:
N2(g) + 3H2(g) 2NH3(g) (balanced?)
51. Which of the following (with specific heat capacity provided) would show the smallest
temperature change upon gaining 155 J of heat?
(A) 25.0 g Au, CAu = 0.128 J/g.°C
(B) 25.0 g Ag, CAg = 0.235 J/g.°C
(C) 50.0 g Al, CAl = 0.903 J/g.°C
(D) 50.0 g Cu, CCu = 0.385 J/g.°C
(E) 25.0 g granite, Cgranite = 0.790 J/g°C
52. Use the standard reaction enthalpies given below to determine ΔH o rxn for the following reaction:
2 NO(g) + O2(g) 2 NO2(g) ΔH o rxn = ?
Given:
N2(g) + O2(g) 2 NO(g) ΔH o rxn = +183 kJ
½ N2(g) + O2(g) NO2(g) ΔH o rxn = +33 kJ
(A) -211 kJ (B) -117 kJ (C) -153 kJ (D) +165 kJ (E) +795 kJ
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53. Which of the following is an acid-base reaction? Select the best answer.
(A). C(s) + O2(g) CO2(g)
(B). 2HClO4(aq) + Ca(OH)2(aq) 2H2O(l) + Ca(ClO4)2(aq)
(C). Fe(s) + 2AgNO3(aq) 2Ag(s) + Fe(NO3)2(aq)
(D). MgSO4(aq) + Ba(NO3)2(aq) Mg(NO3)2(aq) + BaSO4(s)
(E). All of the above are acid base reactions.
54. Give the net ionic equation for the reaction (if any) that occurs when aqueous solutions of K2S
and Fe(NO3)2 are mixed.
(A). Fe 2+
(aq) + S 2-
(aq) FeS(s)
(B). Fe 2+
(aq) + S 2-
(aq) + 2K +
(aq) + 2NO3 - (aq) FeS(s) + 2K
+ (aq) + 2NO3
- (aq)
(C). K +
(aq) + NO3 - (aq) KNO3(s)
(D). Fe 2+
(aq) + S 2-
(aq) + 2K +
(aq) + 2NO3 - (aq) Fe
2+ (aq) + S
2- (aq) + 2KNO3(s)
55. According to the following reaction, what mass of PbCl2 can form from 422 mL of 0.110M KCl
solution? Assume that there is excess Pb(NO3)2.
2KCl(aq) + Pb(NO3)2(aq) PbCl2(s) + 2KNO3(aq) (balanced ?)
(A). 7.19 g
(B). 3.59 g
(C). 6.45 g
(D). 5.94 g
(E). 1.30 g
56. When 10.00 moles of H2(g) react with 5.000 moles of O2(g) to form 10.00 moles of H2O(l) at 25°C
and a constant pressure of 1.00 atm. If 683.0 kJ of heat are released during this reaction, and
PΔV is equal to -37.00 kJ, then
(A). ΔH° = -683.0 kJ and ΔE° = -646.0 kJ. (B). ΔH° = -683.0 kJ and ΔE° = -720.0 kJ. (C). ΔH° = +683.0 kJ and ΔE° = +720.0 kJ. (D). ΔH° = +683.0 kJ and ΔE° = +646.0 kJ.
57. Determine the molarity of a solution formed by dissolving 97.7 g LiBr in enough water to yield
750.0 mL of solution.
(A). 0.130 M (B). 0.768 M (C). 2.30 M (D). 1.50 M (E). 1.18 M
58. Determine the name for aqueous HBr.
(A). bromic acid (B). bromous acid (C). hydrogen bromate (D). hydrobromic acid (E). hydrobromous acid
59. Which one of the following compounds is(/are) soluble in water? Select all that apply.
(A). Ca3(PO4)2 (B). HgS (C). Ni(NO3)2 (D). MgCO3