Mixed Skills Problems (gases, solutions, acids and bases)
Prof. Golestaneh
Note: Problems listed here are at a higher level. Please try solving these only after completing your
assigned textbook homework. Solving these problems help you with the written portion of the upcoming
quizzes and exam(s). Rewrite these problem statements and do all problems in your homework notebook.
Don’t memorize any of these problems. Learn the concept behind each and identify your weaknesses. If
you are not solving these correctly, identify the missing links in your learning. Next, go back to your
notes and study the concepts and examples we did in class and review your textbook homework. The
hardest situation to deal with from both student and instructor’s point of view is for you to hold: “I don’t
know what I don’t know”! Turn this into ‘I know what I don’t know” and work on that by getting the right
help from your instructor and your productive study partners. Work hard, smart and attentively!
1) A tire is inflated (filled) with air to 80. psi (gauge pressure) to a volume of 10.7 L. at a temperature
of 11 ºC. Assume that the volume remains constant after the tire is filled with air.
a) Calculate moles of air that was put into the tire.
b) What happens to the tire when it is driven on a hot road when the tire warms to 60. ºC.?
c) If the tire’s maximum (safe) pressure rating is 80. psi, how many moles of air should be
released from the tire?
2) In a reaction of 35 mL hydrochloric acid solution with excess zinc, hydrogen gas is released. If the
volume of hydrogen gas collected over water at 25 ºC was 2.72 L, at a total pressure of 755 torr,
Assume a solution density of 1.00 g/mL.
a) Calculate mass of hydrogen gas produced.
b) Calculate molarity of hydrochloric acid solution.
© 2013, K. Golestaneh
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Mixed Skills Problems (gases, solutions, acids and bases)
Prof. Golestaneh
3) Hydrogen peroxide, H2O2 decomposes into water and oxygen gas. What volume of oxygen gas
can be collected over water at 30. ºC and a total pressure of 750. torr, when 1.75 L of a 3.5% (by
mass) H2O2 solution decomposes completely?
4) A 455 mL solution of 0.175 M sodium phosphate is mixed with 355 mL 0.295 M barium chloride
solution.
a) Write the overall conventional, total ionic and the net ionic equation for the reaction:
b) Calculate mass of the solid produced.
c) Calculate concentration (M) of all spectator ions.
© 2013, K. Golestaneh
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Mixed Skills Problems (gases, solutions, acids and bases)
Prof. Golestaneh
5) What volume (mL) of 0.203 M NaOH solution is necessary to neutralize 123 mL of 0.132 M
phosphoric acid?
6) 23.6 g of calcium chloride is dissolved in 172 g of water. Te solution density is measured to be
1.23 g/mL.
a) Write the balanced solubility reaction including all states of matter.
b) Calculate mass percent of the solute (calcium chloride).
c) Calculate molarity of the solute.
d) Calculate molarity of dissolved chloride and calcium ions.
7) When a solutions of ammonium chloride and sodium hydroxide react, a gas is released, write the
overall conventional, total ionic and net ionic reactions. Label all acids and bases and use a proper
arrow to show the extent of reaction (complete vs. incomplete).
© 2013, K. Golestaneh
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Mixed Skills Problems (gases, solutions, acids and bases)
Prof. Golestaneh
Answers:
1) a) 2.5 mol b) 94 psi
c) 0.4 mol
2) a) 0.216 g b) 6.1 mol
3) 24 L
4) a) 2PO43- (aq) + 3Ba2+ (aq) → Ba3(PO4)2 b) 21.0 g
c) 0.259 M(Cl‾) , 0.295 M(Na+)
5) 240. mL
6) a) CaCl2 Ca2+ (aq) + 2Cl‾ (aq) b) 12.1%
c) 1.34 M
d) 2.67 M(Cl‾), 1.34 M(Ca2+)
+
7) Net ionic equation:
NH4 (aq) + OH‾(aq)  NH3(g) + H2O (l)
acid
base
base
acid (Reactants being the stronger set)
© 2013, K. Golestaneh
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