Back
Problem 81
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 83b
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?
Problem 86
Water is a good solvent for many substances. What is the molecular basis for this property, and why is it significant?
- Explain the role of water in moderating Earth's climate.
Problem 87
- How is the density of solid water compared to that of liquid water atypical among substances, and why is this significant?
Problem 88
Problem 89
Explain the observed trend in the melting points of the hydrogen halides.
HI -50.8 °C
HBr -88.5 °C
HCl -114.8 °C
HF -83.1 °C
Problem 90
Explain the observed trend in the boiling points of these compounds.
H2Te -2 °C
H2Se -41.5 °C
H2S -60.7 °C
H2O 100 °C
Problem 91
The vapor pressure of water at 25 °C is 23.76 torr. If 0.25 g of water is enclosed in a 1.50-L container, will any liquid be present? If so, what mass of liquid?
Problem 92
The vapor pressure of CCl3F at 300 K is 856 torr. If 3.5 g of CCl3F is enclosed in a 1.0-L container, will any liquid be present? If so, what mass of liquid?
- Four ice cubes at exactly 0 °C with a total mass of 53.5 g are combined with 115 g of water at 75 °C in an insulated container. If no heat is lost to the surroundings, what is the final temperature of the mixture?
Problem 95
Problem 96
A sample of steam with a mass of 0.552 g and at a temperature of 100 °C condenses into an insulated container holding 4.25 g of water at 5.0 °C. Assuming that no heat is lost to the surroundings, what is the final temperature of the mixture?
Problem 99
Air conditioners not only cool air, but dry it as well. A room in a home measures 6.0 m × 10.0 m × 2.2 m. If the outdoor temperature is 30 °C and the partial pressure of water in the air is 85% of the vapor pressure of water at this temperature, what mass of water must be removed from the air each time the volume of air in the room is cycled through the air conditioner? (Assume that all of the water must be removed from the air.) The vapor pressure for water at 30 °C is 31.8 torr.
Problem 100
A sealed flask contains 0.55 g of water at 28 °C. The vapor pressure of water at this temperature is 28.35 mmHg. What is the minimum volume of the flask in order that no liquid water be present in the flask?
Problem 101a
Based on the phase diagram of CO2 shown in Figure 11.39(b), describe the state changes that occur when the temperature of CO2 is increased from 190 K to 350 K at a constant pressure of (a) 1 atm