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- Why is the heat of vaporization of water greater at room temperature than at its boiling point?
Problem 6
- Consider the phase diagram for iodine shown here. a. What is the normal boiling point for iodine? b. What is the melting point for iodine at 1 atm? c. What state is present at room temperature and normal atmospheric pressure? d. What state is present at 186 °C and 1.0 atm?
Problem 8
Problem 40a
Determine the kinds of intermolecular forces that are present in each element or compound. a. HBr
Problem 40b
Determine the kinds of intermolecular forces that are present in each element or compound. b. I2
Problem 41d
Determine the kinds of intermolecular forces that are present in each element or compound. d. CH3OH
Problem 42c
Determine the kinds of intermolecular forces that are present in each element or compound. c. CCl4
Problem 42d
Determine the kinds of intermolecular forces that are present in each element or compound. d. N2
- Arrange these compounds in order of increasing boiling point: a. CH4, b. CH3CH3, c. CH3CH2Cl, d. CH3CH2OH. Explain your reasoning.
Problem 43
Problem 45c
In each pair of compounds, pick the one with the higher boiling point. Explain your reasoning. c. CH3OCH3 or CH3CH3OH
Problem 46b
In each pair of compounds, pick the one with the higher boiling point. Explain your reasoning. b. CH3OH or CH3SH
Problem 47
In each pair of compounds, pick the one with the higher vapor pressure at a given temperature. Explain your reasoning. a. Br2 or I2 b. H2S or H2O c. NH3 or PH3
Problem 48a,c
In each pair of compounds, pick the one with the higher vapor pressure at a given temperature. Explain your reasoning. a. CH4 or CH3Cl c. CH3OH or H2CO
Problem 48b
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 49a,b,c
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 b. KCl and H2O c. Br2 and CCl4
Problem 49d
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 51
Which compound would you expect to have greater surface tension: acetone [(CH3)2CO] or water (H2O)? Explain.
- Why does water wet some surfaces and bead up on others, while mercury beads up on almost all surfaces?
Problem 52
Problem 54
Explain why the viscosity of multigrade motor oils is less temperature-dependent than that of single-grade motor oils.
- Why does water in a glass tube with grease or oil residue display a flat meniscus, whereas water in a clean glass tube displays a concave meniscus?
Problem 55
Problem 56
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 58
Which evaporates more quickly: 100 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.
- Why does spilling room-temperature water over your skin on a hot day cool you down while spilling room-temperature vegetable oil does not?
Problem 59
Problem 63
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 65
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
- This table displays the vapor pressure of nitrogen at several different temperatures. Use the data to determine the heat of vaporization and the normal boiling point of nitrogen. Temperature (K) Pressure (torr) 65 130.5 70 289.5 75 570.8 80 1028 85 1718
Problem 66
Problem 69
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 70
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 71
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.
- Methylamine has a vapor pressure of 344 torr at -25 °C and a boiling point of -6.4 °C. What is the ΔHvap for methylamine?
Problem 72
Problem 73
How much energy is released when 75.2 g of water freezes?