Show:
Gases
Liquids
Solids
Draw and Label
Short Answer and Show Your Work
100
1. Which factor is the most important in determining the average kinetic energy of gas particles?
a. pressure
b. temperature
c. volume of the container
d. mass of the container
What is b?
100
6. When there is a small decrease in temperature, the average kinetic energy of the particles of a liquid
a. decreases.
b. becomes zero.
c. is not changed.
d. increases.
What is a?
100
11. Amorphous solids behave like liquids at certain temperatures because of their
a. particle fluidity.
b. incompressibility.
c. high density.
d. random arrangement.
What is d?
100
16. Draw the phase diagram for water and label the critical point.
100
21. Use the kinetic-molecular theory to explain why liquids are fluids, how liquids diffuse, and why they evaporate.
According to the kinetic-molecular theory, the particles in a liquid can change relative positions but still are influenced by attractive forces. Their ability to move about explains the fluidity of liquids and their ability to diffuse. As some particles at the surface of a liquid gain energy, they overcome the attractive force and vaporize.
200
2. Which characteristic accounts for the fluidity of gases and liquids?
a. strong intermolecular forces
b. elastic collisions between particles
c. particle mobility
d. small particle size
What is c?
200
7. Liquids diffuse more slowly than gases because
a. liquids cannot be compressed.
b. the attractive forces between particles restrict their movement.
c. the particles in a liquid are not mobile.
d. liquids are always at lower temperatures than gases.
What is b?
200
12. When heated, a pure crystalline solid will
a. gradually soften before it melts.
b. melt over a wide temperature range.
c. exhibit a sharply defined melting temperature.
d. melt at a temperature slightly above its freezing temperature.
What is c?
200
17. Label the normal freezing point.
200
22. Define the term equilibrium vapor pressure, and use it to explain the boiling point depressions of substances at elevations higher than sea level.
Equilibrium vapor pressure is the pressure exerted by a vapor in equilibrium with its corresponding liquid at a given temperature. A liquid boils when its equilibrium vapor pressure is equal to atmospheric pressure. At high elevations, there is lowered atmospheric pressure. This means that the equilibrium vapor pressure will equal the lowered atmospheric pressure at a lower temperature.
300
3. According to the kinetic-molecular theory, particles of an ideal gas
a. attract each other but do not collide.
b. repel each other and collide.
c. collide but do not attract each other.
d. do not collide and do not attract or repel each other.
What is c?
300
8. As atmospheric pressure on the surface of a liquid decreases, its boiling point
a. decreases.
b. increases.
c. remains unchanged.
d. shows no correlation.
What is a?
300
13. A solid's molar enthalpy of fusion is the energy that is
a. released when a solid melts.
b. absorbed when a solid melts.
c. needed to transform a solid to a gas.
d. required for equilibrium.
What is b?
300
18. Label the triple point.
300
23. How much energy would be required to melt 32.0 g of ice (18.02 g/mol)? (The molar enthalpy of fusion for water is 6.008 kJ/mol.)
What is 10.7 kJ?
400
4. Which gas is most likely to deviate from ideal gas behavior?
a. Ne
b. CO2
c. NH3
d. H2
What is c?
400
9. What is likely to happen to a liquid mixture of water and rubbing alcohol in an open flask as temperature is increased while pressure stays the same?
a. Both liquids will vaporize at the same rate.
b. Water will vaporize faster.
c. Vaporization and condensation will reach equilibrium.
d. Rubbing alcohol will vaporize faster.
What is d?
400
14. In general, ionic compounds have
a. high boiling points and low melting points.
b. low boiling points and high melting points.
c. high boiling points and high melting points.
d. low boiling points and low melting points.
What is c?
400
19. Label the liquid phase.
400
24. Calculate the molar enthalpy of vaporization of a substance if 0.652 mol of the substance absorbs 6.411 kJ when it melts.
What is 9.83 kJ?
500
5. The kinetic-molecular theory of gases assumes that the particles of an ideal gas are separated by great distances. This implies that the gas particles are considered to have no definite
a. mass.
b. volume.
c. density.
d. energy.
What is b?
500
10. Liquids and solids are much denser than gases because the particles of liquids and solids have a
a. greater mass.
b. closer arrangement.
c. greater volume.
d. smaller volume.
What is b?
500
15. Covalent molecular crystals have very low melting points, while covalent network crystals have very high melting points because
a. the forces that hold molecules together in molecular crystals are weaker than those that hold molecules or atoms together in network crystals.
b. there are more molecules in molecular crystals than in network crystals.
c. network crystals are more intricate crystals.
d. molecular crystals can be either polar or nonpolar, while network crystals are always nonpolar.
What is a?
500
20. Label the critical pressure.
500
25. Calculate the energy released by freezing 13.8 g of a liquid. Its molar mass is 82.9 g/mol, and its molar enthalpy of fusion is 4.60 kJ/mol.
What is 0.776 kJ?