1、A solution is prepared by dissolving 15.0 g of NH3 in 250 g of water. The density of the resulting solution is 0.974 g/mL. The mole fraction of NH3 in the solution is __________.
A、0.922
B、16.8
C、0.0597
D、0.94
E、0.064
2、The vapor pressure of pure water at 25 °C is 23.8 torr. Determine the vapor pressure (torr) of water at 25 °C above a solution prepared by dissolving 35 g of urea (a non-volatile, non-electrolyte, MW = 60.0 g/mol) in 75 g of water.
A、3.3
B、27
C、0.88
D、21
E、2.9
3、The freezing point of ethanol (C2H5OH) is -114.6 °C. The molal freezing point depression constant for ethanol is 2.00 °C/m. What is the freezing point (°C) of a solution prepared by dissolving 50.0 g of glycerine (C3H8O3 a nonelectrolyte) in 200 g of
A、-5.42
B、-114.6
C、-120
D、-115
E、-132.3
4、A solution is prepared by dissolving 6.00 g of an unknown nonelectrolyte in enough water to make 1.00 L of solution. The osmotic pressure of this solution is 0.750 atm at 25.0 °C. What is the molecular weight (g/mol) of the unknown solute?
A、5.12 × 10-3
B、30.6
C、195
D、110
E、16.4
5、The principal reason for the extremely low solubility of NaCl in benzene (C6H6) is the __________.
A、increased disorder due to mixing of solute and solvent
B、strong solvent-solvent interactions
C、weak solvation of Na+ and Cl– by C6H6
D、hydrogen bonding in C6H6
E、strength of the covalent bond in NaCl
6、Pairs of liquids that will mix in all proportions are called __________ liquids.
A、unsaturated
B、polar liquids
C、miscible
D、saturated
E、supersaturated
7、The solubility of oxygen gas in water at 25 °C and 1.0 atm pressure of oxygen is 0.041 g/L The solubility of oxygen in water at 3.0 atm and 25 °C is __________ g/L.
A、0.014
B、0.041
C、0.31
D、3
E、0.12
8、A sample of potassium chlorate (15.0 g) is dissolved in 201 g of water at 70 °C with precautions taken to avoid evaporation of any water. The solution is cooled to 30.0 °C and no precipitate is observed. This solution is __________.
A、saturated
B、unsaturated
C、miscible
D、hydrated
E、supersaturated
9、The concentration of lead nitrate (Pb(NO3 )2) in a 0.726 M solution is __________ molal. The density of the solution is 1.202 g/mL.
A、0.65
B、1.928
C、0.819
D、0.476
E、0.755
10、The concentration of a benzene solution prepared by mixing 12.0 g C6H6 with 38.0 g CCl4 is __________ molal.
A、0.622
B、4.04
C、0.24
D、0.508
E、0.316
