Chapters 7 & 8

8) Which is a spectator ion from the following complete ionic equation: H+(aq) + Br-(aq) + K+ (aq) + OH-(aq) → H2O(l) + K+(aq) + Br- (aq) A) K+ B) H+ C) OH- D) H2O E) none of the above

Answer: A

1) Which of the following statements about balancing reactions is FALSE? A) If there is no coefficient or subscript, a one is implied. B) When coefficients are added the type of compounds is changed in the chemical reaction. C) Subscripts are multiplied by the coefficients to determine the number of atoms in a compound. D) Coefficients are added to compounds to ensure both sides of the reaction have equal numbers of each atom. E) All of the above statements are true.

Answer: B

4) What is the limiting reactant for the following reaction given we have 2.6 moles of HCl and of Ca(OH)2? Reaction: 2HCl + Ca(OH)2 → 2H2O + CaCl2 A) Ca(OH)2 B) HCl C) H2O D) CaCl2 E) not enough information

Answer: B

7) Considering the following precipitation reaction: Pb(NO3)2(aq) + 2KI(aq) → PbI2(s) + 2KNO3(aq) Which ion(s) would NOT be present in the net ionic equation? A) Pb2+, NO3- B) K+, NO3- C) K+, Pb2+ D) K+, I- E) All the above ions are in the net ionic equation.

Answer: B

10) Which of the following statements about redox reactions is FALSE? A) Oxidation is the loss of electrons. B) Reduction is the gain of electrons. C) A reaction can result in either oxidation or reduction, not both. D) A reaction involving elemental oxygen is a redox reaction. E) All of the above statement are true.

Answer: C

3) Iron metal reacts with oxygen to produce iron(III) oxide. If you have 12.0 moles of iron for complete reaction, you need: A) 9.0 moles of O2 and produce 3.0 moles of Fe2O3. B) 12.0 moles of O2 and produce 24.0 moles of Fe2O3. C) 9.0 moles of O2 and produce 6.0 moles of Fe2O3. D) 4.5 moles of O2 and produce 3.0 moles of Fe2O3. E) none of the above

Answer: C

5) Consider the following equation: CO + 2 H2 → CH3OH △H rxn = -128 kJ Calculate the amount of heat (in kJ) associated with complete reaction of 8.08 g H2. A) -1024 kJ B) -1034 kJ C) -256 kJ D) -512 kJ E) none of the above

Answer: C

2) Suppose two chemical reactions are linked together in a way that the O2 produced in the first reaction goes on to react completely with Mg to form MgO in the second reaction. Reaction one: 2 KClO3 → 3 O2 + 2 KCl Reaction two: 2 Mg + O2 → 2 MgO If you start with 4 moles of KClO3, how many moles of MgO could eventually form? A) 2 moles B) 4 moles C) 6 moles D) 12 moles E) none of the above

Answer: D

6) Which of the following equations is NOT balanced properly? A) 2Cr + 6HCl → 2CrCl3 + 3H2 B) 2NaHCO3 → Na2CO3 + CO2 + H2O C) Cr2(SO4)3 + 6KOH → 2Cr(OH)3 + 3 K2SO4 D) 4NH3 + 14O2 → 4NO2 + 6H2O E) none of the above

Answer: D

9) When a solution of MgCl2 and one of AgNO3 are mixed, the net ionic equation is: A) Mg2+(aq) + 2Cl-(aq) + 2Ag+(aq) + 2NO3- (aq) → Mg2+(aq) + 2NO3-aq) + 2AgCl(s) B) Mg2+(aq) + 2Cl-(aq) + 2Ag+(aq) + 2NO3- (aq) → Mg(NO3)2 (aq) + 2 AgCl(s) C) Mg2+(aq) + 2NO3-(aq) → Mg(NO3)2(aq) D) Cl-(aq) + Ag+(aq) → AgCl(s) E) none of the above

Answer: D