States Quiz

A little Quiz on the States of Matter

1. Which of the following does NOT describe the critical point of a liquid?

A) the temperature and pressure at whch a liquid's meniscus disappears
B) the point where the vapor pressure curve intersects the fusion temperature curve
C) the highest temperature at which a liquid can exist
D) the temperature and pressure at which a liquid and its vapor are identical
E) the highest temperature at which it is possible to obtain a liquid from its vapor by increasing pressure

ANSWER: B

2. Different types of crystalline solids are held together by:

A) dipole-dipole interactions
B) ionic attractions
C) hydrogen bonds
D) covalent bonds
E) pi bonds only

ANSWER: E

3. Fairly low melting point, a crystal that readily conducts heat and electricity and which is easily deformed but difficult to cleave, are all characteristics of what type of crystalline solid?

A) molecular
B) ionic
C) metallic
D) network covalent
E) none of these answers

ANSWER: C

4. Which of the substances below would produce the hardest, most brittle crystals?

A) SiC
B) Xe
C) Cu
D) KNO₃
E) H₂O

ANSWER: A

5. A container holds a small amount of liquid and its vapor in equilibrium. If the volume of the container is decreased, which of the following has occurred once equilibrium is reestablished?

A) the temperature is lower
B) the temperature is higher
C) the pressure is higher
D) the pressure is lower
E) none of these

ANSWER: B

6. A crystal and its melt readily conduct electricity. The crystal also has a luster and is easily deformed. Thus, it is:

A) a covalent network crystal
B) an ionic crystal
C) not enough data is given
D) a molecular crystal
E) a metallic crystal

ANSWER: E

7. Liquid Q is a polar solvent and liquid R is a nonpolar solvent. On the basis of this information, you would expect:

A) both liquids to be miscible with a third liquid T
B) liquid Q to be miscible with liquid R
C) NaCl to be soluble to both Q and R
D) liquid Q and H₂O to be miscible

ANSWER: D

8. If a substance has a heat of condensation of -1.46 kJ/g and a heat of sublimation of 4.60 kJ/g, what is its heat of solidification in kJ/g?

A) 4.60 - 1.46
B) -(4.60 + 1.46)
C) 1.46 - 4.60
D) 4.60 + 1.46
E) none of these answers

ANSWER: C

9. When a liquid is in equilibrium with its vapor in a closed container:

A) the rate at which molecules from the liquid phase enter the gas phase exactly equals the rate at which molecules from the gas phase pass into the liquid phase
B) a change in temperature will not change the pressure in the container
C) the amount of gas in the container must exactly equal the amount of liquid
D) molecules cannot go from the liquid phase to the gas phase because the amount of liquid in the container is constant

ANSWER: A

10. If one compares compound A composed of nonpolar molecules with compound B composed of polar molecules, and both molecules have the same molecular formula then it is true that:

A) both compounds have the same boiling point
B) A boils at a lower temperature than B
C) B will not boil
D) B boils at a lower temperature than A
E) none of these answers

ANSWER: B

11. Under which of the following conditions will vaporization best occur?

A) high mass, large surface area, high kinetic energy
B) weak forces between molecules, high kinetic energy, large surface area
C) high molecular energy, small surface area
D) low kinetic energy, strong molecular forces, large surface area
E) small surface area, low kinetic energy, low molecular mass

ANSWER: B

12. Which of the following does NOT decrease rate of vaporization?

A) closing container lid
B) increasing forces between molecules
C) increasing mass of molecule
D) decreasing temperature
E) decreasing surface area

ANSWER: A

13. A liquid will "wet" a surface if:

A) the liquid has a lesser density than the surface
B) the forces between the liquid molecules are weak
C) the liquid has a low vapor pressure
D) the forces between the molecules and the surface are greater than the forces between the molecules of the liquid
E) none of these answers

ANSWER: D

14. X rays are NOT:

A) diffracted by crystals
B) radiation of wavelength approximating 1 Angstrom
C) visible to the naked eye
D) used to determine the structure of molecules
E) produced using high energy electrons

ANSWER: C

15. According to the Bragg equation, if the wavelength of the investigating X rays is decreased, assuming that the same crystal is being investigated, the following will occur:

A) the interplanar spacing will decrease
B) the diffraction angle will will decrease
C) the order of the reflection will decrease
D) none of these answers

ANSWER: D

16. If 34 g of a solid of mol mass = 174 g/mol requires 21.3 kJ to melt it, what is the molar heat of fusion in kJ/mol?

A) (21.3)(174)(34)
B) (21.3/174)(34)
C) (21.3/174)/34
D) (21.3)(174/34)
E) none of these

ANSWER: D

17. Which of the following factors does NOT affect the normal boiling point of a liquid?

A) atmospheric pressure
B) strength of forces between molecules
C) rate of evaporation
D) rate of condensation
E) none of these answers

ANSWER: A

18. A liquid is in equilibrium with its vapor. If some of the vapor is allowed to escape, what is the immediate result?

A) condensation rate decreases
B) vaporization rate increases
C) condesation rate increases
D) vaporization rate decreases
E) none of these

ANSWER: A

19. A liquid has a normal boiling point of 78 ^oC and its vapor pressure is 400 mmHg at 50 ^oC. To compute the molar heat of vaporization, one needs:

A) the mole weight
B) nothing, enough information is given
C) the vapor pressure at another temperature
D) the specific heat
E) none of these

ANSWER: B

20. Which of the following statements concerning molecules in the liquid state is true?

A) Cohesive forces are not important
B) The molecules contract to fit the size of the container
C) The molecules have no motion
D) The molecules are in a patterned (oriented) arrangement
E) The molecules are mobile and relatively close together

ANSWER: E

21. The triple point of H₂O is at 4.58 mmHg and +0.01 ^oC. Some H₂O at -50 C is heated to 120 ^oC at a constant pressure of 0.5 atm. The changes of state occurring in this process are:

A) solid to gas
B) solid to liquid to gas
C) liquid to gas
D) solid to liquid
E) no change in state occurs at constant pressure

ANSWER: B

22. Surface tension is thought to be due to:

A) surface area trying to increase
B) air absorbed on the surface
C) solute concentrated on the surface
D) surface molecules having lower energy than bulk molecules
E) none of these answers

ANSWER: E

23. All sides are equal in length and all angles are right angles. There is an atom at each corner and one in the absolute center. This is a:

A) face-centered cubic cell
B) simple cubic cell
C) unit cell
D) body-centered cubic cell
E) none of these answers

ANSWER: D

24. All sides are equal in length and all angles are right angles. There is an atom at each corner and one at the center of each side. This is a:

A) body-centered cubic cell
B) simple cubic cell
C) unit cell
D) face-centered cubic cell
E) none of these answers

ANSWER: D

25. An arrangement in which every other layer is identical (ABABABAB) is:

A) octahedral holes
B) tetrahedral holes
C) hexagonal close packed
D) cubic close packing
E) none of these answers

ANSWER: C

26. A crystal does not conduct electricity, yet its melt and aqueous solutions do. It is hard and brittle and melts at a high temperature. What type of crystal is it?

A) a molecular crystal
B) a covalent network crystal
C) a metallic crystal
D) an ionic crystal
E) Not enough information is given

ANSWER: D

27. A crystal does not conduct electricity, even after melting. It is hard and brittle and melts at a very high temperature. What type of crystal is it?

A) an ionic crystal
B) Not enough data is given
C) a covalent network crystal
D) a metallic crystal
E) a molecular crystal

ANSWER: C

28. A liquid has a molar heat of vaporization of 22.7 kJ/mol. Its normal boiling point is 459K. What is the vapor pressure, in mmHg, at 70 ^oC?

ANSWER: 102 mmHg

Given the data below, determine the molar enthalpy change of vaporization of each liquid and its normal boiling point.

29. COCl2 , p₁ = 40 mmHg, T₁= -50.3 ^oC, p₂= 100 mmHg, T₂= -35.6 ^oC

ANSWER: 27.4 kJ/mol, 5.0 ^oC

30. Rb, p₁= 1.00 mmHg, T₁= 297 ^oC, p₂= 400 mmHg, T₂= 620 ^oC

ANSWER: 78.5 kJ/mol, 678 ^oC

31. Which of the following compounds has the largest lattice energy:

MgCO₃ , Na₂CO₃ , Al₂(CO₃)₂

ANSWER: Na₂CO₃

32. Which of the following compounds has the highest boiling point: NH₃, H₂O, HF

ANSWER: H₂O

33. The process in which a gas is transformed into a solid is called:

A) vaporization
B) condensation
C) solidification
D) deposition
E) none of these

ANSWER: D

34. Which of the following compounds has the highest solubility: CaCl₂, CaI₂, SrI₂

ANSWER: SrI₂

MULTIPLE CHOICE

35. The factor that has the largest effect on vapor pressure is

A) liquid surface area
B) molecular dipole moment
C) presence of H bonding
D) liquid mole weight
E) volume available for vapor

ANSWER: C

36. When the vapor pressure of a liquid equals atmospheric pressure, the temperature of the liquid equals:

A) 100 ^oC
B) the boiling point
C) the normal boiling point
D) the vaporization point
E) none of these

ANSWER: B

SHORT ANSWER

37. The normal boiling point of acetone is 56.2 ^oC and the molar heat of vaporization is 32.0 kJ/mol. At what temperature will acetone boil under a pressure of 50.0 mmHg?

ANSWER: -6.0 ^oC

Use the data of Table 13-1 to determine the vapor pressure at the given temperature

38. acetone, T = 15.0 ^oC

ANSWER: 143 mmHg

39. SO₂, T = -50.0 ^oC

ANSWER: 84.6 mmHg

Use the data of Table 13-1 to determine the temperature needed to attain the given vapor pressure

40. methanol p = 15 mmHg

ANSWER: -9.3 ^oC

41. bromine p = 250 mmHg

ANSWER: 31 ^oC