Question
Which of the following processes is exothermic, given the following: N_2(g) + 2 O_2(g) rightarrow N_2O_4(l) Delta H degree = 9.67 kJ/mol N_2(g) + 2 O_2(g) rightarrow 2 NO_2(g) Delta H degree = 67.70 kJ mol A) 2 N_2(g) + 4 O_2(g) + 2 N_2O_4(l) B) 1/2 N_2(g) + O_2(g) + 1/2 N_2O_4(l) C) N_2O_4(l) rightarrow N_2(g) + 2 O_2(g) D_ 2 N_2(g) + 4 O_2(g) rightarrow 2 NO_2(g) + N_2O_4(l) E) 2 N_2(g) + 4 O_2(g) rightarrow 4 NO_2(g) The reaction Cu(s) + 2 AgNO_3(aq) rightarrow Cu(NO_3)_2(aq) + 2 Ag(s) is best classified as a(n) A) acid-base neutralization reaction. B) double replacement reaction. C) oxidation-reduction reaction. D) precipitation reaction. What is the molar concentration of sodium ions in a 0.350 M Na_3PO_4 solution? A) 0.117 M B) 0.350 M C) 1.05M D) 1.40M What is the molecular geometry of BrF_4^-? A) seesaw B) square planar C) square pyramidal D) tetrahedral In the reaction AgNO_3(aq) + HI(aq) rightarrow AgI(s) + HNO_3(aq) the spectator ions are A) Ag^+ and NO_3^- B) Ag^+ and I^- C) H^+ and I^- D) H^+ and NO_3^- Which species functions as the oxidizing agent in the following reduction-oxidation reaction? 5 Fe^2+(aq) + MnO_4^-(aq) + 8 H^+(aq) rightarrow Mn^2+(aq) + 5 Fe^3+(aq) + 4 H_2O(l) A) Fe^2+(aq) B) H^+(aq) C) Mn^2+(aq) D) MnO_4^-(aq)
Explanation / Answer
30) Answer (C).
N2O4 (l) ---------> N2 (g) + O2 (g) H = -9.67 Kj/mol
H = - ve means exothermic.
31) Answer (B). Double replacement
32) Answer (C) 1.05 M.
Na3PO4 -------> 3 Na^+ + PO4^3-.
1 mole Na3PO4 gives 3 moles Na^+, so 0.35 M gives 3× 0.35 = 1.05M.
33) Answer (B).Square planar.There are 4 bond pairs and 2 lone pairs,hence suitable geometry as per VSEPR theory is square planar.
34) Answer (D) H^+ and NO3^- .A spectator ion is an ion that exists in the same form on both the reactant and product sides of a chemical reaction. The ion is unchanged on both sides of a chemical equation and does not affect equilibrium.
35)Answer (D)MnO4^-. Oxidizing agent itself get reduced.
