Figure P20.45 shows a phase diagram of carbon dioxide in terms of pressure and temperature, a. Use the phase diagram to explain why dry ice (solid carbon dioxide) sublimates into vapor at atmospheric pressure rather than melting into a liquid. At what temperature does the dry ice sublimate when at atmospheric pressure? b. Estimate what pressure would be needed to liquefy carbon dioxide at room temperature.

It is the morning of a day that will become hot. You just purchased drinks for a picnic and are loading them, with ice, into a chest in the back of your car. (a) You wrap a wool blanket around the chest. Does doing so help to keep the beverages cool, or should you expect the wool blanket to warm them up? Explain your answer. (b) Your younger sister suggests you wrap her up in another wool blanket to keep her cool on the hot day like the ice chest. Explain your response to her.

A glass coffee pot has a circular bottom with a 9.00-cm diameter in contact with a heating element that keeps the coffee warm with a continuous heat transfer rate of 50.0 W (a) What is the temperature of the bottom of the pot, if it is 3.00 mm thick and the inside temperature is 60.0C ? (b) If the temperature of the coffee remains constant and all of the heat transfer is removed by evaporation, how many grams per minute evaporate? Take the heat of vaporization to be 2340kJ/kg.

A cylinder of volume 50.0 cm3 made of Pyrex glass is full to the brim with acetone. If the cylinder and acetone are warmed by 30.0C, (a) what is the change in volume of the glass? (b) Of the acetone? (c) Will any acetone spill out of the cylinder? (See Section 10.3.)

A sample of gas with a thermometer immersed in the gas is held over a hot plate. A student is asked to give a step-by-step account of what makes our observation of the temperature of the gas increase. His response includes the following steps, (a) The molecules speed up. (b) Then the molecules collide with one another more often. (c) Internal friction makes the collisions inelastic, (d) Heat is produced in the collisions. (e) The molecules of the gas transfer more energy to the thermometer when they strike it, so we observe that the temperature has gone up. (f) The same process can take place without the use of a hot plate if you quickly push in the piston in an insulated cylinder containing the gas. (i) Which of the parts (a) through

If a gas undergoes an isobaric process, which of the following statements is true? (a) The temperature of the gas doesnt change. (b) Work is done on or by the gas. (c) No energy is transferred by heat to or from the gas. (d) The volume of the gas remains the same. (e) The pressure of the gas decreases uniformly.

Unreasonable Results (a) An automobile mechanic claims that an aluminum rod fits loosely into its hole on an aluminum engine block because the engine is hot and the rod is cold. If 1he hole is 10.0% bigger in diameter than the 22.0C rod, at what temperature will the rod be the same size as the hole? (b) What is unreasonable about this temperature? (2) Which premise is responsible?

(a) Calculate the rate of heat conduction through house walls that are 13.0 cm thick and have an average thermal conductivity twice that of glass wool. Assume there are no windows or doors. The walls' surface area is 120 m2 and their inside surface is at 18.0 , while their outside surface is at 5.00 . (b) How many 1-kW room heaters would be needed to balance the heat transfer due to conduction?

On a cold winter day. you buy roasted chestnuts from a street vendor. Into the pocket of your down parka you put the change he gives you: coins constituting 9.00 g of copper at 12.0C. Your pocket already contains 14.0 g of silver coins at 30.0C. A short time later the temperature of the copper coins is 4.00C and is increasing at a rate of 0.500C/s. At this time, (a) what is the temperature of the silver coins and (b) at what rate is it changing?