Chapter 7

Question 1

Molality (m) equation

Answer 1

m = mol solute/kg solvent

Question 2

Molarity (M) equation

Answer 2

M = mol solute/ L solution

Question 3

What are the 5 compounds that make ionic compounds SOLUBLE?

Answer 3

group 1 cations

NO3- (nitrate)

ClO4- (perchlorate)

C2H3O2- (acetate)

NH4+ (ammonium)

Question 4

What are the 7 compounds that make ionic compounds INSOLUBLE?

Answer 4

Ag+ (silver)

Pb 2+ (lead)

S^2- (sulfide)

OH- (hydroxide)

Hg2^2+ (dimercury)

CO3^2- (carbonate)

PO4^3- (phosphate)

Question 5

Gas dissolves more at _____ temperatures and ____ pressures.

Answer 5

low, high

think of a can of cold soda!

Question 6

If the amount of solute dissolved is greater than the solubility, then we have a _____ solution.

On the other hand, if the solute dissolved is less than the solubility, then an ____ solution is formed.

Answer 6

supersaturated

unsaturated

Question 7

If a compound is a strong electrolyte, it will thus have a low

a) freezing point
b) boiling point

Answer 7

A

Question 8

The vapor pressure of a solution of two volatile liquids will be_____ the vapor pressure of the pure liquids

Answer 8

between

Question 9

Determine the vapor pressure of a solution of chloroform and dichloromethane, where the mole fraction of chloroform is 0.40. The vapor pressure of chloroform is 160 mmHg, while that of dichloromethane is 540 mmHg.

  A. 160 mm Hg
  B. 350 mmHg
  C. 380 mmHg
  D. 388 mmHg
  E. 540 mmHg

Answer 9

D

0.40 (160) + 0.60 (540)

Question 10

Consider a solution that contains 0.1 mol of benzene and 0.2 mol of toluene. What is the vapor pressure of this solution at 25 oC? The vapor pressure of pure benzene and pure toluene is 75 torr and 21 torr, respectively.

Answer 10

39 torr

Ptotal= Ptoluene + Pbenzene

(Raoult’s Law: P=X*P°

(X=mole fraction, P°=pure pressure)

Pvapor=(0.1/0.1+0.2)(75 torr)+(0.2/0.1+0.2)(21 torr)=25+14=39 torr (B)