Substance X is known to exist at 1 atm in the solid, liquid, or vapor phase, depending on the temperature. Additionally, the values of these other properties of X have been determined: melting point enthalpy of fusion density 95. °C 9.00 kJ/mol 2.40 g/cm (solid) boiling point enthalpy of vaporization 135. °C 38.00 kJ/mol 31. J-K mol (solid) 2.10 g/mL (liquid) heat capacity 61. J.Kmol (liquid) You may also assume X behaves as an ideal gas in the vapor phase. 61. JK mol (vapor) D Suppose a small sample of X at 50 °C is put into an evacuated flask and heated at a constant rate until 15.0 kJ/mol of heat has been added to the sample. Graph the temperature of the sample that would be observed during this experiment. temperature (°C) 150- 140- 130- 120- 110- 100- 90- 80- 70 60 15 B X G 00. ?

Referring to Figure 9.7, state what phase(s) is/are present at (a) 1 atm, 100C. (b) 0.5 atm, 100C.(c) 0.8 atm. 50C.

8.87 Use the vapor pressure curves illustrated here to answer the questions that follow. (a) What is the vapor pressure of ethanol (C2H5OH) at 60°C? (b) Considering only carbon disulfide (CS2) and ethanol, which has the stranger intermolecular forces in the liquid state? (c) At what temperature does heptane (C7H16) have a vapor pressure of 500 mm Hg? (d) What are the approximate normal boiling pains of each of the three substances? (e) At a pressure of 400 mm Hg and a temperature of 70°C, is each substance a liquid, a gas, or a mixture of liquid and gas?

If you've ever opened a bottle of rubbing alcohol or other solvent on a warm day, you may have heard a little “whoosh” as the vapor that had built up above the liquid escapes. Describe on a microscopic basis how a vapor pressure builds up in a closed container above a liquid. What processes in the container give rise to this phenomenon?

The heats of vaporization of liquid O2, liquid Ne, and liquid methanol, CH3OH, are 6.8 kJ/moL 1.8 kJ/mol, and 34.5 kJ/mol, respectively. Are the relative values as you would expect? Explain.

Referring to Figure 9.7, state what phase(s) is (are) present at (a) 1 atm, 10C. (b) 3 mm Hg, 20C. (c) 1000 mm Hg, 75C.

Carbon tetrachloride, CCl4, was once used as a dry cleaning solvent, but is no longer used because it is carcinogenic. At 57.8 C, the vapor pressure of CCl4 is 54.0 kPa, and its enthalpy of vaporization is 33.05 kJ/mol. Use this information to estimate the normal boiling point for CC14.

The following data are the equilibrium vapor pressure of limonene, C10H16, at various temperatures. (Limonene is used as a scent in commercial products.) (a) Plot these data as ln P versus 1/T so that you have a graph resembling the one in Figure 11.13. (b) At what temperature does the liquid have an equilibrium vapor pressure of 250 mm Hg? At what temperature is it 650 mm Hg? (c) What is the normal boiling point of limonene? (d) Calculate the molar enthalpy of vaporization for limonene using the Clausius-Clapeyron equation.

A 1.50-g sample of methanol (CH3OH) is placed in an evacuated 1.00-L container at 30 C. (a) Calculate the pressure in the container if all of the methanol is vaporized. (Assume the ideal gas law, PV = nRT.) (b) The vapor pressure of methanol at 30 C is 158 torr. What mass of methanol actually evaporates? Is liquid in equilibrium with vapor in the vessel?

Define critical temperature and critical pressure. In terms of the kinetic molecular theory, why is it impossible for a substance to exist as a liquid above its critical temperature?