Chem 134 Exam 3 (Take Home). Questions with Correct Answers

Chem 134 Exam 3 (Take Home)

The net ionic equation for the dissolution of zinc metal (Zn) in aqueous hydrobromic
acid (HBr) is

(a) Zn(s) + 2H+ (aq) -- Zn2+(aq) + H2(g)
(b) Zn(s) + 2HBr-(aq) -- ZnBr2(aq) +2H+(aq)
(c) 2Zn(s) + H+(aq) -- 2Zn2+(aq) + H2(aq)
(d) Zn(s) + 2HBr(aq) -- ZnBr2(s) + 2H+(aq)
(e) Zn(s) + 2Br-(aq) -- ZnBr2(aq) - answer(D) Zn(s) + 2HBr(aq) -- ZnBr2(s) + 2H+(aq)

What mass (g) of potassium chloride is contained in 430.0 mL of a potassium chloride
solution that has a chloride ion concentration of 0.193 M?

(a) 0.386
(b) 0.0643
(c) 0.0830
(d) 6.19
(e) 12.37 - answer(D) 6.19

What volume (mL) of a 3.45 M lead nitrate solution must be diluted to 450.0 mL to make
a 0.990 M solution of lead nitrate?

(a) 101
(b) 56
(c) 45
(d) 129
(e) 109 - answer(D) 129

The spectator ions in the reaction between aqueous chloric acid and aqueous barium
hydroxide are

(a) ClO3- and Ba2+
(b) H+ and OH-
(c) OH- and ClO3-
(d) H+, OH-, ClO3- and Ba2+
(e) H+ and Ba2+ - answer(A) ClO3- and Ba2+

What volume (mL) of 7.48*10^-2 M phosphoric acid can be neutralized with 115 mL of
0.244 M sodium hydroxide?

(a) 750
(b) 188