Semester Exam Review

• For the reaction NBr3(g) + 3 H2O(g) → 3 HOBr(s) + NH3(g), enthalpy = -113 kJ/mol rxn. The spontaneity of this reaction is likely to decrease as the temperature increases.


  1)increase; temperature increases 2)decrease; temperature decreases 3)decrease; temperature increases 4)increase; moles of water increase 5)stay constant; moles of water increase 6)stay constant; temperature changes 7)decreases; moles of water increases
• If the value of ΔG°rxn is negative, then the process will occur spontaneously under standard conditions.
• A reaction which is exothermic will be spontaneous at all temperatures if the change in entropy is positive.


  1)no; positive 2)all; negative 3)all; positive 4)no; negative
• Consider 3 electrolysis experiments: 1- 1 Faraday of electricity is passed through a solution of AgNO3. 2- 1 Faraday of electricity is passed through a solution of Zn(NO3)2. 3- 1 Faraday of electricity is passed through a solution of Bi(NO3)3. Which of the following is true? 2


  1)equal masses of all 3 metals are produced. 2)equal numbers of moles of all 3 metals are produced. 3)the reaction producing the smallest mass of metal is the AgNO3 solution. 4)2 times as many moles of metallic Zn are produced than metallic Ag.
• For the two half reactions: Zn2+ + 2 e − −→ Zn(s), E ◦ = −0.7 V, and Fe3+ + 3 e − −→ Fe(s), E ◦ = −0.1 V. In a galvanic cell, what is the standard cell potential? 0.6V


  1)-0.7 V 2)-0.1 V 3)0.0V 4)0.6V 5)-0.6V
• What is the mass of oxygen gas in a 12.6 L container at 3.00◦C and 8.96 atm? Answer in units of g.

  159.43g
• 60000 coulombs of electricity was passed through a solution of lead(II) nitrate (Pb(NO3)2). How much metallic lead would be deposited? Answer in units of g. Answer: 64.41g
• Which of the following reactions as written corresponds to a standard formation reaction? Answer: 5


  1: CO2(s) → CO2(g) 2: 2 H2(g) + O2(g) → 2 H2O(ℓ) 3: SO2(g) + 1 2 O2(g) → SO3(g) 4: 2H (g) + O2(g) → H2O2 (ℓ) 5: Na(s) + 1 2 Cl2(g) → NaCl(s)
• A reaction mixture that consisted of 0.35 mol H2 and 1.55 mol I2 was introduced into a 4 L flask and heated. At the equilibrium, 60% of the hydrogen gas had reacted. What is the equilibrium constant Kc for the reaction H2(g) + I2(g) ⇀↽ 2 HI(g) at this temperature?

  Answer: 0.9403
• Consider the reaction 2 HgO(s) ⇀↽ 2 Hg(ℓ) + O2(g). What is the form of the equilibrium constant K for the reaction? 1) K = [O2] 2) K = [Hg]^2 [O2] 3) K = [Hg]^2 [O2] [HgO]^2 4) K = [O2] [HgO]^2 5) None of the other answers is correct.

  Answer: 1
• What is the molarity of the nitric acid if 20.87 mL react with 0.198 grams of sodium carbonate? 1) 0.144 M 2) 1.14 × 10−4 M 3) 0.179 M 4) 0.438 M 5) 0.0895 M

  Answer: 3
• A sample of oxalic acid (H2C2O4, with two acidic protons), of volume 47.32 mL was titrated to the stoichiometric point with 21.46 mL of 0.28 M NaOH(aq). What is the molarity of the oxalic acid? Answer in units of M.

  Answer: 0.0635M
• Which has the greatest number of hydrogen atoms? Answer: 4


  1)100g of a substance that is 2% H by mass 2) 1020 hydrogen atoms 3) 100 g of water 4) 20 g of hydrogen gas 5) 5 g of an unknown compound
• If 39.0 g of C6H6 reacts with excess chlorine and produces 30.0 g of C6H5Cl in the reaction C6H6 + Cl2 → C6H5Cl + HCl , what is the percent yield of C6H5Cl?

  Answer: 53.4%
• The combustion of ammonia produces NO and water. If the chemical reaction for this process is properly balanced using the smallest possible integers, what is the sum of the coefficients for the products?

  Answer: 10
• A compound consists of 65.45% C, 5.492% H, and 29.06% O on a mass basis and has a molar mass of 110 g/mol. Determine the molecular formula of the compound.

  Answer: C6H6O2
• Which one of the following is a water-soluble, weak electrolyte? 1) KBr 2) H2SO4 3) H2CO3 4) NH4ClO 5) Ca(OH)2

  Answer: 3
• Which of the following has the same electron configuration as Ca2+ ? 1) S2− 2) F− 3) Mg2+ 4) Ca 5) Ne

  Answer: 1
• Which pair of elements is most likely to form an ionic compound? 1) sodium and aluminum 2) magnesium and fluorine 3) oxygen and chlorine 4) nitrogen and sulfur

  Answer: 2