S_02

Question 1

What do colligative properties depend on

Answer 1

concentration of solute particles present

Question 2

Vapor pressure lowering formula

Answer 2

∆P = Xsolute P^0solvent

Question 3

P^0solvent :

Answer 3

: Vapor pressure of pure solvent

Question 4

Boiling point elevation formula

Answer 4

ΔT b = m kb
m = molality

Question 5

Kb =?

Answer 5

boiling point elevation constant

Question 6

Melting point depression formula

Answer 6

ΔT f = mkf
m = molality

Question 7

Kf= ?

Answer 7

freezing point depression cnst

Question 8

Osmotic pressure formula

Answer 8

π = (nRT) / V= MRT
M : molarity

Question 9

Rate of evaporations depends on which two factors

Answer 9

temperature —— surface area of liquid

Question 10

Is rate of evaporation cnst

Answer 10

Yes

Question 11

Pressure increase - decrease - cnst with evaporation?

Answer 11

increase

Question 12

When gaseous particles collide with the surface they

Answer 12

Condense

Question 13

As concentration in the gas phase increases, more gaseous particles

Answer 13

Collide with the surface

Question 14

Rate of evaporation =

Answer 14

rate condensation

Question 15

Rate of condensation =

Answer 15

Rate of evaporation

Question 16

Pgas=

Answer 16

equilibrium Vapor pressure

Question 17

Rate of evaporation formula

Answer 17

Psolv = Xsolv x P^0solv

Question 18

Raoult’s Law

Answer 18

∆P = X solute x P^0 solv

Question 19

A solution of nonvolatile solute in benzene (C6H6) has a vapor pressure (Psolv) of 91.5 torr at 25oC. Calculate Xsolute if Pobenzene = 93.9 torr at 25o C.

Answer 19

0.026 p.8

Question 20

Calculate the vapor pressure (in torr) at 25 oC of a solution containing 99.5 g sucrose
(C12H22O11 , MM = 342.34 g/mol) and 300.0 g of water. The vapor pressure of pure
water at 25 oC is 23.8 torr.

Answer 20

23.39 p.9

Question 21

What is an ideal solution

Answer 21

Solution that obeys Raoult’s law throughout the entire range of composition

Question 22

Define boiling point elevation

Answer 22

Temperature at which the Vapor pressure of a liquid is equal at atmospheric pressure

Question 23

Calculate the boiling point (Tb) of a 0.32 m I2 solution in benzene knowing that the boiling point of pure benzene is 80.10 oC and kb benzene = 2.53oC/m.

Answer 23

80.91 C p. 10

Question 24

Calculate the molar mass (MM) of an unknown solute if a solution of 1.00 g of this
solute in 15.0 g of acetic acid (solvent) has a boiling point of 120.17 oC. Pure acetic
acid has a boiling point of 117.90 oC and its kb = 3.07 oC/m

Answer 24

1. Calculate ∆Tb
2. Calculate m
3. Calculate mol solute
4. Calculate molar mass (MM) solute

90.2g/mol p. 11

Question 25

Define freezing point depression

Answer 25

Solute particles prevent solvent molecules from aggregating to form a solid

Question 26

Van’t Hoff factor (i) equation ?

Answer 26

i = (measured colligative property) / (expected value for a non electrolyte)

Question 27

∆ Property = i [Solute] x constant

Answer 27

i [Solute] x cnst

Question 28

∆Tf = imkf ∆Tb = imkb

Answer 28

For non electrolytes

Question 29

What is the ideal value for the Van’t Hoff factor for Ca(NO3)2 ?

Answer 29

3 p.18

Question 30

A 0.031 m solution of CuSO4 in H2O has a fp = -0.075 oC (Kf water = 1.86 oC/m). a) Calculate the Van’t Hoff factor i for this solution. b) Would i be larger or smaller or same for a 0.050 m solution of CuSO4? Explain

Answer 30

A) 1.3 B) smaller P.18

Question 31

What is osmosis?

Answer 31

Diffusion of water from a lower solute concentration to one of higher solute concentration through a semipermeable membrane

Question 32

Define osmotic pressure (π)

Answer 32

The pressure required for no net transport of solvent to occur across a semipermeable membrane

Question 33

A 10.00 mL aqueous solution of 0.263 g of hemoglobin (Hb) has a Π = 7.51 torr at 25 oC. Calculate the molar mass of hemoglobin.

Answer 33

6.51 x 10^4 g/mol P.23

Question 34

At 25 oC Pobenzene = 384 torr, Potoluene = 133 torr. A mixture is made by combining 1.20 mol toluene and 3.60 mol benzene. A) what is the partial pressure of toluene above the liquid? B)What is the partial pressure of benzene above the liquid? C) What is the total pressure above the liquid? D)What is the mole fraction of toluene in the vapor phase?

Answer 34

A) 1. Find mol fraction of toluene in the liquid. 2. Calculate the partial pressure of toluene above the liquid. 33.2 torr B)288torr C)321torr D) 0.103 Page. 26

Question 35

What is the deviation from raoults law

Answer 35

It is obeyed by dilute mixtures only