Chapter 18 Review Solutions

1
Chapter 18 Review - Solutions

• Charles Page High School
• Dr. Stephen L. Cotton

2
Chapter 18 Review - definitions

• saturated solution
• colligative properties
• miscible
• molarity (M)
• unsaturated solution

3
Chapter 18 Review - definitions

• immiscible
• concentrated solution
• Henrys law
• supersaturated solution
• dilute solution
• molality (m)

4
Chapter 18 Review

• Increasing the temperature of a liquid-solid
  solution will
• What will usually make a substance dissolve
  faster in a solvent?

( increase the rate and amount that dissolves )
( agitation raising the temperature and also
crushing the substance to a powder )
5
Chapter 18 Review

• To increase the solubility of a gas at constant
  temperature and 202 kPa pressure from 0.85 g/L to
  5.1 g/L, the pressure would have to be increased
  to

( 1212 kPa )
6
Chapter 18 Review

• If the pressure of a gas above a liquid is
  decreased (at constant temperature), the
  solubility of the gas in the liquid
• An ionic compound has a solubility of 30 g/100 mL
  water at room temperature. A solution with 70
  g/250 mL is

( decreases )
( unsaturated )
7
Chapter 18 Review

• How many mL of alcohol are in 240 mL of 95.0
  (v/v) alcohol solution?
• What happens if more solvent is added to a
  solution?

( 228 mL )
( the molarity decreases )
8
Chapter 18 Review

• What is the molarity of a 200 mL solution in
  which 0.2 mol of sodium bromide is dissolved?
• What is the percent (m/v) of a water solution
  that contains 60 g of calcium chloride, and that
  has a volume of 400 mL?

( 1.0 M )
( 15 )
9
Chapter 18 Review

• Name 3 colligative properties of a solution that
  we have studied.
• If one mole of each of these solutes are added to
  the same amount of water, which has the highest
  boiling point? A) CuCl2 b) Al2(SO4)3

( boiling-point elevation vapor-pressure
lowering and freezing-point depression )
( b )
10
Chapter 18 Review

• AT, ST, or NT
• The solubility of a solute can be increased by
  cooling the solvent.
• Grinding a solute increases the rate at which it
  would dissolve.

( ST )
( AT )
11
Chapter 18 Review

• AT, ST, or NT
• As an open bottle of a carbonated beverage warms,
  the concentration of dissolved carbon dioxide
  decreases.
• 100 mL of 5.0M NaCl is more concentrated than 1.0
  L of a 1.0 M NaCl solution.

( AT )
( AT )
12
Chapter 18 Review

• AT, ST, or NT
• The amount of NaCl in 100 mL of a 5.0 M NaCl
  solution is greater than that in 1.0 L of a 1.0 M
  NaCl solution.
• As the temperature of a solvent increases, the
  solubility of a gaseous solute increases.

( NT )
( NT )
13
Chapter 18 Review

• AT, ST, or NT
• 50 mL of a 16 solution (v/v) of ethyl alcohol in
  water contains 16 mL of water.
• An unsaturated solution contains less solute than
  required for equilibrium.

( NT )
( AT )
14
Chapter 18 Review

• AT, ST, or NT
• A saturated solution has a large amount of solute
  compared to solvent.
• If a crystal of a substance added to aqueous
  solution dissolves, then the original solution
  containing that substance was supersaturated.

( ST )
( NT )
15
Chapter 18 Review

• How would you prepare 250 mL of 0.60 M Al2(SO4)3
  solution from a 2.0 M Al2(SO4)3 stock solution?

( Add 75 mL of the 2.0 M stock solution to enough
distilled water to make 250 mL total )
16
Chapter 18 Review

• Calculate the molarity of a solution prepared by
  dissolving 95.5 grams of KNO3 in enough water to
  make 750 mL of solution.

( 1.26 M )
17
Chapter 18 Review

• A gas has a solubility in water of 16.9 g/L at 15
  oC and 505 kPa of pressure. What is its
  solubility in water at 15 oC and 606 kPa of
  pressure?

( 20.28 g/L )
18
Chapter 18 Review

• Calculate the boiling point of a solution that
  contains 0.900 mol of K3PO4 dissolved in 2750
  grams of water. (Kb for water 0.512 oC/m)

( 100.67 oC )
19
Chapter 18 Review

• Calculate the molality of a solution prepared by
  dissolving 175 grams of KNO3 in 1250 grams of
  water.

( 1.39 m )
20
Chapter 18 Review

• A solution of 10.6 g of a nonvolatile compound in
  55.0 g of water freezes at -3.26 oC. What is the
  molecular mass of the solute? (Assume that the
  solute exists as molecules in the solution. Kf
  for water 1.86 oC/m)

( 109.9 g/mol )