Unformatted text preview: Problem set 1 Chapter 12 Fall 2011.
Name___________________________________ R.Lopez de la Vega
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) Which should be least soluble in water?
B) C) D) 2) What is the mole fraction of oxygen in a gas mixture that is 22% oxygen and 78% nitrogen by
D) 0.22 2) 3) Stainless steel is an example of a ________ solution.
C) solid/liquid 3)
D) liquid/liquid 4) In the process of dissolving ionic compounds, the cations and anions are separated from the
crystal lattice and surrounded by an ordered shell of solvent molecules. If the solvent is water,
the dissolved ions are said to be
D) hydrated. 4) 5) Commercial cold packs often contain solid NH4NO 3 and a pouch of water. The temperature
of the pack drops as the NH4NO 3 dissolves in water. Therefore, for the dissolving of
NH4NO 3 in water,
A) ΔHsoln is positive and ΔSsoln is positive.
B) ΔHsoln is negative and ΔSsoln may be negative or positive.
C) ΔHsoln is positive and ΔSsoln may be negative or positive.
D) ΔHsoln is negative and ΔSsoln is positive. 5) 6) The rubbing alcohol sold in drug stores often is composed of 70% isopropyl alcohol and 30%
water. In this solution
A) water is the solvent.
B) isopropyl alcohol is the solvent.
C) both water and isopropyl alcohol are solvents.
D) neither water nor isopropyl alcohol is a solvent. 6) 1 7) A solution is prepared by dissolving 17.75 g sulfuric acid, H2SO4, in enough water to make
100.0 mL of solution. If the density of the solution is 1.1094 g/mL, what is the mole fraction
H2SO4 in the solution?
D) 0.0181 7) 8) What is the weight percent of vitamin C in a solution made by dissolving 1.30 g of vitamin C,
C6H8O6, in 55.0 g of water?
D) 2.31% 8) 9) A solution is prepared by dissolving 17.75 g sulfuric acid, H2SO4, in enough water to make
100.0 mL of solution. If the density of the solution is 1.1094 g/mL, what is the molality?
A) 0.1775 m H2SO4
B) 0.1810 m H2SO4
C) 1.940 m H2SO4
D) 1.810 m H2SO4 9) 10) A solution is 2.25% by weight NaHCO 3. How many grams of NaHCO3 are in 450.0 g of
A) 0.500 g
B) 225 g
C) 200 g
D) 10.1 g 10) 11) A solution of LiCl in water is 18.0 wt% LiCl. What is the mole fraction of LiCl?
D) 0.0933 11) 12) The solubility of gaseous solutes in liquid solvents is greater when the
A) partial pressure of the gas above the solution is increased.
B) external pressure over the solution is increased.
C) external pressure is decreased.
D) partial pressure of the solvent is increased. 12) 13) In general, as the temperature increases, the solubility of gases in water ________ and the
solubility of most solids in water ________.
A) decreases, increases
B) decreases, decreases
C) increases, decreases
D) increases, increases 13) 14) Which of the following does not affect the solubility of a solute in a given solvent?
A) rate of stirring
B) polarity of the solvent
C) temperature of the solvent and solute
D) polarity of the solute
14) 15) At 25.0°C, a solution has a concentration of 3.179 M and a density of 1.260 g/mL. The density
of the solution at 50.0°C is 1.249 g/mL. What is the molarity of the solution at 50.0°C?
A) 3.179 M
B) 3.151 M
C) 2.545 M
D) 3.230 M 15) 16) A solution of LiCl in water has X LiCl = 0.0500. What is the molality?
A) 2.92 m LiCl
B) 2.77 m LiCl
C) 5.26 m LiCl 16) 17) What volume of 0.716 M KBr solution is needed to provide 10.5 g of KBr?
A) 123 mL
B) 14.7 mL
C) 63.2 mL 2 D) 2.60 m LiCl
D) 7.52 mL 18) Aqueous solutions of 30% (by weight) hydrogen peroxide, H 2O2, are used to oxidize metals or
organic molecules in chemical reactions. Given that the density of the solution is 1.11 g/mL,
calculate the molarity.
A) 9.79 M
B) 0.794 M
C) 6.78 M
D) 12.6 M 3 18) Answer Key
Testname: UNTITLED1 1) B
18) A 4 ...
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