Exam II Review

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Exam II Review

• Chemistry 1211
• Dr. Clower

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• 1. Which of the following methods is correct for
  calculating the moles of Al3 in 125 mL of 0.234
  M Al(NO3)3?

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• 2. A mass of 12.0 g of calcium chloride is
  diluted to a volume of 250 mL in a volumetric
  flask. Which of the equations below is a correct
  method for determining the chloride ion
  concentration?

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• 3. All of the following ionic compounds are
  soluble in water EXCEPT
• Fe(OH)3
• Sr(OH)2
• Al(NO3)3
• KI
• CuCl2

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• 4. Precipitation reactions occur
• When group 1 cations are mixed with group 17
  anions
• When insoluble reactants are mixed
• When ionic compounds react to form non-ionic
  products
• Predominantly with halide salts
• When soluble ionic reactants combine to form
  insoluble products

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• 5. If aqueous solutions of sodium sulfate and
  barium chloride are mixed, a white precipitate
  forms. What is the identity of the precipitate?
• Na2Ba
• NaCl2
• NaCl
• BaSO4
• Ba2SO4

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• 6. Identify all of the spectator ions in the
  reaction below.
• Zn(OH)2(s) 2H(aq) 2NO3-(aq) ?
• Zn2(aq) 2NO3-(aq) 2H2O
• Zn(OH)2
• NO3-
• Zn2
• H
• H and NO3-

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• 7. What net ionic reaction occurs when aqueous
  solutions of potassium carbonate and iron(III)
  bromide are mixed?
• CO32-(aq) 2Fe(aq) ? Fe2(CO3)(s)
• 3CO32-(aq) 2Fe3(aq) ? Fe2(CO3)3(s)
• 3CO32-(aq) 6Fe(aq) ? 3Fe2CO3(s)
• 3K2CO3(aq) 2Fe3(aq) 6Br-(aq) ? Fe2(CO3)3(s)
  6KBr(s)
• No reaction occurs

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• 8. What is the balanced net ionic equation for
  the neutralization of aqueous solutions of sodium
  hydroxide and perchloric acid, HClO4?
• OH-(aq) HClO4(aq) ? H2O ClO4-(aq)
• NaOH(aq) H(aq) ? H2O Na(aq)
• Na(aq) ClO4-(aq) ? NaClO4(s)
• OH-(aq) H(aq) ? H2O
• None of the above are correct

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• 9. Which of the following is a weak acid?
• HBr
• HCl
• HF
• HI
• HClO4

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• 10. NH3(aq) is a
• strong base
• strong acid
• weak base
• weak acid
• neither an acid nor a base

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• 11. Assign oxidation numbers to each atom in
  sulfuric acid.
• H 1 S 6 O -2
• H 1 S 7 O -2
• H 1 S 7 O -8
• H -1 S -2 O 0
• H -1 S 6 O -8

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• 12. Identify which species is reduced and which
  is oxidized in the reaction below.
• SO3(g) H2O ? H2SO4(l)
• H2O is reduced, SO3 is oxidized
• H2O is reduced, no oxidation occurs
• SO3 is reduced, H2O is oxidized
• H2SO4 is both reduced and oxidized
• The reaction is not a redox reaction

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• 13. Identify the reaction type for the reaction
  between potassium metal and hydrochloric acid.
• 2K(s) 2H(aq) ? 2K(aq) H2(g)
• Precipitation
• Acid-base
• Oxidation-reduction
• Both answers a and c
• None of the above

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• 14. Heat capacity is defined as
• 4.18 J/gºC
• 4.18 cal/gºC
• the amount of heat necessary to raise the
  temperature of 1 gram of a substance by 1ºC.
• the amount of heat necessary to raise the
  temperature of a system by 1ºC.
• none of the above

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• 15. Aluminum has a specific heat of 0.902 J/gºC.
  How many joules of heat are required to change
  the temperature of 8.50 grams of aluminum from
  25.0ºC to 93.4ºC?
• 7.67 J
• 71.7 J
• 192 J
• 483 J
• 524 J

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• 16. Copper has a specific heat of 0.382 J/gºC. If
  2.51 g of copper absorbs 2.75 J of heat, what is
  the change in temperature?
• 0.419ºC
• 2.63ºC
• 2.87ºC
• 4.12ºC
• 6.90ºC

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• 17. A coffee-cup calorimeter contains 50.0 g of
  water at 60.51ºC. A 12.4 g piece of graphite at
  24.21ºC is placed in the calorimeter. The final
  temperature of the water and the carbon is
  59.02ºC. Calculate the specific heat of carbon.
  The specific heat of water is 4.18 J/gºC.
• 0.328 J/gºC
• 0.639 J/gºC
• 0.692 J/gºC
• 0.721 J/gºC
• 1.39 J/gºC

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• 18. A chemical reaction in a bomb calorimeter
  raises the temperature of the calorimeter from
  20.22ºC to 23.14ºC. If the heat capacity of the
  calorimeter is 8.44 kJ/ºC, calculate the heat
  evolved in the reaction.
• 2.89 kJ
• 5.52 kJ
• 9.12 kJ
• 11.36 kJ
• 24.6 kJ

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• 19. All of the following statements are true
  except
• the enthalpy change of an endothermic reaction is
  positive.
• at constant pressure the heat flow for a reaction
  equals the change in enthalpy.
• DH for a reaction is equal in magnitude but
  opposite in sign to DH for the reverse reaction.
• enthalpy is a state function.
• enthalpy change is dependent upon the number of
  steps in a reaction.

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• 20. Methane, CH4, reacts with oxygen to produce
  carbon dioxide, water, and heat.
• CH4 (g) 2 O2 (g) ? CO2 (g) 2 H2O (l) DH
  -890.3 kJ
• What is the value of DH if 5.00 g of CH4 is
  combusted?
• -157 kJ
• -277 kJ
• -445 kJ
• -714 kJ
• -1.43x104 kJ

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• 21. Determine the heat of reaction for the
  decomposition of one mole of benzene to acetylene
• C6H6(l) ? 3 C2H2 (g)
• given the following thermochemical equations
• 2 C6H6 (l) 15 O2 (g) ? 12 CO2 (g) 6 H2O (g)
  DH -6271 kJ
• 2 C2H2 (g) 5 O2 (g) ? 4 CO2 (g) 2 H2O (g)
  DH -2511 kJ
• 631 kJ
• 1262 kJ
• 3760 kJ
• 6902 kJ
• 8782 kJ

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• 22. The molar enthalpies of formation for H2O (l)
  and H2O (g) are -285.8 kJ and -241.8 kJ,
  respectively. How much heat is released when 25 g
  of water condenses from the gas to the liquid
  phase?
• -2.4 kJ
• -32 kJ
• -61 kJ
• -88 kJ
• -1100 kJ

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• 23. If not handled carefully, ammonium
  perchlorate can decompose violently according to
  the thermochemical equation below.
• 2 NH4ClO4 (s) ? N2 (g) Cl2 (g) 2 O2 (g) 4
  H2O (g) DH -375.6 kJ
• The enthalpy of formation of H2O (g) is -241.8
  kJ. Calculate the enthalpy of formation of
  ammonium perchlorate.
• -295.8 kJ
• -156.4 kJ
• 66.9 kJ
• 133.8 kJ
• 561.1 kJ

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• 24. All of the following statements concerning
  bond enthalpies are correct EXCEPT
• formation of a bond is an endothermic process.
• the bond energy of a multiple bond is greater
  than that of a single bond.
• bond energies between two different atoms are
  approximations.
• the energy required to break a bond is positive.
• a reaction is expected to be exothermic if the
  bonds of the products are stronger than those of
  the reactants.

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• 25. In which of the reactions below is DH an
  enthalpy of formation?
• S8 (s) 8 O2 (g) ? 8 SO2 (g)
• CaO (s) H2O (l) ? Ca(OH)2 (s)
• H2 (g) Cl2 (g) 4 O2 (g) ? 2 HClO4 (l)
• Cu (s) I2 (s) ? CuI (s)
• CH4 (g) 2 O2 (g) ? CO2 (g) 2 H2O (g)