Free Printable Olympiad Colligative Properties

1.

A portion of the phase diagram of elemental sulfur is shown below. Which statement about sulfur is correct?

a)

Rhombic sulfur cannot be sublimed without first converting to monoclinic sulfur.

b)

The conversion of rhombic sulfur to monoclinic sulfur is exothermic.

c)

Rhombic sulfur is denser than monoclinic sulfur.

d)

At atmospheric pressure, monoclinic sulfur cannot be in equilibrium with liquid sulfur.

2.

The diagram is a microscopic view of a snapshot of a substance at equilibrium, with the circles representing molecules and the arrows the molecules' velocities. What state of matter is depicted?

a)

Solid

b)

Liquid

c)

Gas

d)

Plasma

3.

The melting point of water decreases with increasing pressure. Which is the best explanation for this observation?

a)

Liquid water is denser than solid water at 0 degrees Celsius.

b)

Melting of ice is endothermic at 0 degrees Celsius.

c)

The vapor pressure of liquid water is lower than the vapor pressure of

d)

Solid and liquid water cannot coexist at equilibrium at 0 degrees Celsius at pressures different from 1 atm.

4.

A portion of the phase diagram of uranium hexafluoride $\left(UF_6\right)$ is shown.

Which statements are correct?

I. $UF_6$ sublimes at atmospheric pressure.

II. At 80 degrees Celsius and 1.5 atm, only $UF_{6\left(g\right)}$ is present at equilibrium.

a)

I only

b)

II only

c)

Both I and II

d)

Neither I nor II

5.

What state of matter corresponds to the diagram shown?

a)

Gas

b)

Liquid

c)

Amorphous Solid

d)

Crystalline Solid

6.

Which aqueous solution exhibits the largest freezing point depression?

a)

1.0m KBr

b)

0.75m $C_6H_{12}O_6$

c)

0.5m $MgCl_2$

d)

0.25m $Ga_2\left(SO_4\right)_3$

7.

The concentration of an aqueous solution of a nonvolatile, monoprotic acid is measured first by freezing point depression and then by boiling point elevation. the solution is found to be 0.93m by freezing point depression and to be 0.82m by boiling point elevation. Which is the best explanation for this discrepancy?

a)

Ionization of the acid is markedly exothermic.

b)

The solution associates partially into dimers at lower temperatures.

c)

The volume of the solution is greater at higher temperatures.

d)

The boiling point elevation constant for water is smaller than its freezing point depression constant.

8.

An aqueous solution of potassium sulfate $\left(K_2SO_4\right)$ has a freezing point of -2.24 degrees Celsius. What is its molality?

$\left(K_f=1.86\degree C\cdot m^{-1}\right)$

a)

0.401m

b)

0.602m

c)

1.20m

d)

4.17m

9.

A solution of 20.0g of which hydrated salt dissolved in 200g water will have the lowest freezing point?

a)

$CuSO_4\cdot5H_2O\ \left(M=250\right)$

b)

$NiSO_4\cdot6H_2O\ \left(M=263\right)$

c)

$MgSO_4\cdot7H_2O\ \left(M=246\right)$

d)

$Na_2SO_4\cdot10H_2O\ \left(M=286\right)$

10.

Which aqueous solution has the highest boiling point?

a)

1.0m acetic acid, $CH_3OOH$

b)

1.0m sulfuric acid, $H_2SO_4$

c)

1.0m phosphoric acid, $H_3PO_4$

d)

1.0m glucose, $C_6H_{12}O_6$

11.

Which of the following would lead to an increase in the vapor pressure of a liquid?

I. Increasing the temperature

II. Adding a nonvolatile solute

a)

I only

b)

II only

c)

Both I and II

d)

Neither I nor II

12.

Which solute, when dissolved in 1kg water, will give the solution with the highest boiling point?

a)

50g ethylene glycol, $HOCH_2CH_2OH$

b)

50g hydroxyacetic acid, $HOCH_2COOH$

c)

50g glycerol, $HOCH_2CHOHCH_2OH$

d)

50g glyoxal, $HCOCHO$

Olympiad Colligative Properties

Total questions: 12

Worksheet time: 24mins

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