Gen. Chem. - Chap 10
Choose the correct answer for each question.
 

1The Pb2+ content in a sample of drinking water was found to be 0.000007 % by mass. What is the concentration of the Pb2+ in ppb?
7 ppb
70 ppb
700 ppb
7000 ppb

2How many grams of NaNO3 are in 255.0 grams of a 4% by mass NaNO3 solution?
10.2 g
25.8 g
4.00 g
49.5 g

3An example of an electrolyte would be...
NH3
sugar
CH3OH
KBr

4Calculate the osmotic pressure of a solution containing 0.73 g of CH3OH in 10.0 mL of solution at 25C. (R = 0.0821 L-atm/mol-K)
1.79 atm
55.8 atm
149.8 atm
1786 atm.

5Which of the following substances is LEAST likely to be soluble in water?
KCl
C2H5OH
NH3
C5H12

6What volume of 12 M HCl is required to make 456 mL of 4.5 M HCl?
45 mL
124 mL
171 mL
199 mL

7Find the molality of a 6.0 M NH3 solution with a density of 0.96 g/mL.
9.6 m
7.0 m
6.0 m
1.6 m

8Calculate the freezing point of a solution containing 6.20 g of glucose (C6H12O6) in 25 g of water. Kf for water = 1.86 kgC/mol
+2.56C
-2.56C
-3.56C
-5.78C

950.0 g of an unknown electrolyte is dissolved in 200.0 g of water. The f.p. of the solution was found to be -7.49C. What is the molar mass of the solute? (Kf = 1.86)
62 g/mol
135.7 g/mol
180 g/mol
220 g/mol

10Which of the following would you expect to become LESS soluble in water as the temperature increases?
KCl (s)
methanol (l)
methane (g)
none of the above