Mastering Phase Change Problems for DAT Exam Success

VI. Phases of matter: Solid, Liquid, and Gas questions

Phase of matter and phase change problems

This chapter includes 22 practice questions on phases of matter, phase changes, and solution properties. Allow about one minute per question. After completing the test, select “See Result” to review your score, answer choices, and explanations. Correct answers are marked in green, and incorrect answers are marked in red.

PHASES OF MATTER: SOLID, LIQUID, AND GAS TEST 1

1 / 22

Which of the following is NOT a property of a liquid?

A. No attractive forces between particles

B. Surface tension

C. Viscosity

D. Adhesion

E. Fluidity

2 / 22

Which statement is INCORRECT?

A. Among similar liquids at the same temperature, a higher normal boiling point generally corresponds to a lower vapor pressure.

B. A liquid boils when its vapor pressure equals the external pressure.

C. Surface tension helps small liquid droplets form nearly spherical shapes.

D. Particles in a liquid are fixed in a rigid arrangement.

E. Gas particles move randomly.

3 / 22

The phase change from gas to solid is called __________, and the phase change from gas to liquid is called __________.

A. Sublimation, fusion

B. Deposition, condensation

C. Freezing, vaporization

D. Sublimation, condensation

E. Vaporization, condensation

4 / 22

Which arrows represent phase changes with ΔH < 0 and ΔS_system < 0?

A. 1, 2, 3

B. 4, 5, 6

C. 2, 4, 5

D. 1, 3, 6

E. 3, 4, 5

5 / 22

Iodine and dry ice can absorb heat and change directly from solid to gas. What is this phase change called?

A. Sublimation

B. Vaporization

C. Fusion

D. Freezing

E. Deposition

6 / 22

Which statement about the phase diagrams is INCORRECT?

A. Graph I represents H₂O, and graph II represents CO₂.

B. In graph I, the melting point increases as pressure increases.

C. In graph II, the boiling point increases as pressure increases.

D. The liquid–gas equilibrium boundary has a positive slope in both diagrams.

E. Within the subcritical region shown, sufficiently increasing temperature and decreasing pressure can convert liquid to gas in either diagram.

7 / 22

Which arrow represents melting ice by increasing pressure at constant temperature near the ice–liquid equilibrium boundary?

Water phase diagram with five numbered phase-change arrows

A. 1

B. 2

C. 3

D. 4

E. 5

8 / 22

Which changes increase the amount of CO₂ dissolved in a carbonated beverage?

A. Decrease temperature and increase CO₂ partial pressure

B. Increase temperature and decrease CO₂ partial pressure

C. Decrease temperature and decrease CO₂ partial pressure

D. Increase temperature and increase CO₂ partial pressure

E. None of the above

9 / 22

Which statement does NOT describe the triple point of a pure substance?

A. Solid, liquid, and gas coexist in equilibrium.

B. Liquid and gas become indistinguishable.

C. All three phases are at the same equilibrium pressure.

D. All three phases are at the same equilibrium temperature.

E. The specified three phases coexist at a unique temperature and pressure.

10 / 22

How much heat is released when 36.0 g of water vapor at 100.0 °C and 1 atm condenses and the resulting liquid cools to 70.0 °C? Use M(H₂O) = 18.0 g/mol, ΔH_vap = 40.7 kJ/mol, and a constant liquid molar heat capacity of 75.4 J/(mol·°C).

A. 45 kJ

B. 85.9 kJ

C. 172 kJ

D. 1547 kJ

E. 1655 kJ

11 / 22

Which expression gives the heat absorbed, in joules, when 9 g of ice at −20 °C melts and the resulting liquid water warms to 30 °C at 1 atm? Use M(H₂O) = 18 g/mol. Let A and C be the numerical molar heat capacities of ice and liquid water in J/(mol·°C), and let B be the numerical molar enthalpy of fusion in J/mol. Assume constant heat capacities.

A. (A)(9)(20) + (B)(9) + (C)(9)(30)

B. (A)(9)(20) + (B)(9)(30) + (C)(9)(30)

C. (A)(9/18)(30) + (B)(9) + (C)( 9/18)(30)

D. (A)(9/18)(20) + (B)(9/18) + (C)(9/18)(30)

E. (A)(9/18)(20) + (B)(9/18)(30) + (C)(9/18)(30)

12 / 22

Which listed effects are colligative properties of ideal dilute solutions containing a nonvolatile solute?

I. The identity-dependent attractive forces between solute and solvent particles

II. Osmotic pressure

III. An increase in the surface area of the solvent

IV. Freezing-point depression and vapor-pressure lowering

A. I and II

B. I and IV

C. I, II, and III

D. II and IV

E. All of the above

13 / 22

What is the approximate boiling point at 1 atm of a solution containing 11.0 g of CaCl₂ in 90.0 g of water? Assume ideal behavior and complete dissociation (i = 3). Use M(CaCl₂) = 111 g/mol, K_b = 0.51 °C·kg/mol, and a pure-water boiling point of 100.0 °C.

A. 120.2 °C

B. 110.1 °C

C. 105.6 °C

D. 101.7 °C

E. 98.3 °C

14 / 22

Approximately how many kilograms of water are needed to make a solution containing 116 g of NaCl freeze at −0.50 °C? Assume ideal behavior and complete dissociation (i = 2). Use M(NaCl) = 58.44 g/mol, K_f = 1.86 °C·kg/mol, and a pure-water freezing point of 0.00 °C.

A. 8 kg

B. 10 kg

C. 13 kg

D. 15 kg

E. 18 kg

15 / 22

Which aqueous solution has the lowest freezing point? Assume ideal behavior, complete dissociation of each salt, no association or reaction, and no dissociation of the molecular solutes. All concentrations are molalities.

A. 0.300 m CaCl₂

B. 0.200 m glucose, C₆H₁₂O₆

C. 0.200 m Al₂(SO₄)₃

D. 0.500 m urea, CO(NH₂)₂

E. 0.300 m Na₂SO₄

16 / 22

Dissolving 5.00 g of a nonvolatile nonelectrolyte in 100.0 g of a hypothetical solvent raises its boiling point by 1.65 °C. The solvent has K_b = 5.95 °C·kg/mol. Assuming ideal behavior (i = 1), which formula has a molar mass consistent with the calculated value?

A. C₉H₈O₄

B. C₆H₆

C. CHCl₃

D. C₄H₁₀O

E. C₂H₆O

17 / 22

Seawater freezes at a lower temperature than fresh water. Which of A–D is NOT related to this effect? If all four are related, choose E.

A. Antifreeze in a vehicle

B. Lower freezing point of the solution than the pure solvent

C. Calcium chloride on the road

D. Colligative properties

E. All of A–D are related.

18 / 22

A solution contains 47.0 g of MgCl₂ and 54.0 g of water. What is the analytical mole fraction of water on a component basis, counting MgCl₂ formula units before dissociation rather than individual ions? Use M(MgCl₂) = 95.21 g/mol and M(H₂O) = 18.02 g/mol.

A. 0.86

B. 0.14

C. 0.33

D. 0.67

E. 0.28

19 / 22

What is the partial vapor pressure of water above a solution containing 23.0 g of ethanol, C₂H₅OH, and 72.0 g of water at 70 °C? Assume an ideal solution that obeys Raoult’s law. Use molar masses of 46.0 g/mol for ethanol and 18.0 g/mol for water, and a pure-water vapor pressure of 234.0 mmHg.

A. 26 mmHg

B. 208 mmHg

C. 226 mmHg

D. 328 mmHg

E. 460 mmHg

20 / 22

What is the osmotic pressure of a 5.00 L aqueous solution containing 188 g of MgCl₂ at 27.0 °C? Assume ideal behavior and complete dissociation (i = 3). Use M(MgCl₂) = 95.2 g/mol and R = 0.08206 L·atm/(mol·K).

A. 0.9 atm

B. 2.6 atm

C. 9.6 atm

D. 29.2 atm

E. 37.6 atm

21 / 22

A 5.00 L aqueous sucrose solution has an osmotic pressure of 182.4 mmHg at 300.0 K. How many moles of sucrose, C₁₂H₂₂O₁₁, does it contain? Assume ideal behavior (i = 1), use 760 mmHg = 1 atm, and use R = 0.08206 L·atm/(mol·K).

A. 4.87 × 10⁻² mol

B. 0.08 mol

C. 0.4 mol

D. 0.8 mol

E. 2.0 mol

22 / 22

What is the equilibrium concentration of dissolved CO₂, in mol/L, at a CO₂ partial pressure of 380 mmHg and 25 °C? Use Henry’s law in the form c = k_HP, with k_H = 3.2 × 10⁻² mol/(L·atm), and 760 mmHg = 1 atm.

A. 1.6×10^-2

B. 6.4×10^-2

C. 8.4×10^-2

D. 12.2

E. 15.6

Your score is

The average score is 40%