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Problem 36a
Determine the kinds of intermolecular forces that are present in each element or compound. a. Kr
Problem 36b
Determine the kinds of intermolecular forces that are present in each element or compound. b. NCl3
Problem 36d
Determine the kinds of intermolecular forces that are present in each element or compound. d. HF
Problem 37d
Determine the kinds of intermolecular forces that are present in each element or compound. d. He
Problem 38c
Determine the kinds of intermolecular forces that are present in each element or compound. c. CH3OH
Problem 38d
Determine the kinds of intermolecular forces that are present in each element or compound. d. I2
Problem 41c
In each pair of compounds, pick the one with the higher boiling point. Explain your reasoning. c. CH4 or CH3CH3
Problem 44b
In each pair of compounds, pick the one with the higher vapor pressure at a given temperature. Explain your reasoning. b. CH3CH2CH2OH or CH3OH
Problem 44c
In each pair of compounds, pick the one with the higher vapor pressure at a given temperature. Explain your reasoning. c. CH3OH or H2CO
Problem 45a
Determine whether each pair of compounds forms a homogeneous solution when combined. For those that form homogeneous solutions, indicate the type of forces that are involved. a. CCl4 and H2O
Problem 45d
Determine whether each pair of compounds forms a homogeneous solution when combined. For those that form homogeneous solutions, indicate the type of forces that are involved. d. CH3CH2OH and H2O
Problem 47
Which compound would you expect to have greater surface tension: acetone [(CH3)2CO] or water (H2O)? Explain.
Problem 50
Explain why the viscosity of multigrade motor oils is less temperature-dependent than that of single-grade motor oils.
Problem 52
When a thin glass tube is put into water, the water rises 1.4 cm. When the same tube is put into hexane, the hexane rises only 0.4 cm. Explain.
Problem 54
Which evaporates more quickly: 55 mL of water (H2O) in a beaker or 100 mL of acetone [(CH3)2CO] in an identical beaker under identical conditions? Is the vapor pressure of the two substances different? Explain.
Problem 59
Suppose that 0.95 g of water condenses on a 75.0-g block of iron that is initially at 22 °C. If the heat released during condensation goes only to warming the iron block, what is the final temperature (in °C) of the iron block? (Assume a constant enthalpy of vaporization for water of 44.0 kJ/mol.)
Problem 61
This table displays the vapor pressure of ammonia at several different temperatures. Use the data to determine the heat of vaporization and normal boiling point of ammonia.
Temperature (K) Pressure (torr)
200 65.3
210 134.3
220 255.7
230 456.0
235 597.0
Problem 63
Ethanol has a heat of vaporization of 38.56 kJ>mol and a normal boiling point of 78.4 °C. What is the vapor pressure of ethanol at 15 °C?
Problem 64
Benzene has a heat of vaporization of 30.72 kJ/mol and a normal boiling point of 80.1 °C. At what temperature does benzene boil when the external pressure is 445 torr?
Problem 65
Carbon disulfide has a vapor pressure of 363 torr at 25 °C and a normal boiling point of 46.3 °C. Find ΔHvap for carbon disulfide.
Problem 67
How much energy is released when 65.8 g of water freezes?
Problem 68
Calculate the amount of heat required to completely sublime 50.0 g of solid dry ice (CO2) at its sublimation temperature. The heat of sublimation for carbon dioxide is 32.3 kJ/mol.
Problem 69
An 8.5-g ice cube is placed into 255 g of water. Calculate the temperature change in the water upon the complete melting of the ice. Assume that all of the energy required to melt the ice comes from the water.
Problem 70
How much ice (in grams) would have to melt to lower the temperature of 352 mL of water from 25 °C to 5 °C? (Assume the density of water is 1.0 g/mL.)
Problem 73
Consider the phase diagram shown here. Identify the states present at points a through g.
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Problem 75
Nitrogen has a normal boiling point of 77.3 K and a melting point (at 1 atm) of 63.1 K. Its critical temperature is 126.2 K and its critical pressure is 2.55 * 104 torr. It has a triple point at 63.1 K and 94.0 torr. Sketch the phase diagram for nitrogen. Does nitrogen have a stable liquid state at 1 atm?
Problem 76
Argon has a normal boiling point of 87.2 K and a melting point (at 1 atm) of 84.1 K. Its critical temperature is 150.8 K and its critical pressure is 48.3 atm. It has a triple point at 83.7 K and 0.68 atm. Sketch the phase diagram for argon. Which has the greater density, solid argon or liquid argon?
Problem 77a
The phase diagram for sulfur is shown here. The rhombic and monoclinic states are two solid states with different structures. a. Below what pressure does solid sulfur sublime?
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Problem 77b
The phase diagram for sulfur is shown here. The rhombic and monoclinic states are two solid states with different structures. b. Which of the two solid states of sulfur is more dense?
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Problem 80
Water is a good solvent for many substances. What is the molecular basis for this property, and why is it significant?
