The temperature on a sample of pure X held at 6.8 atm and -243. °C is increased until the sample sublimes. The temperature is then held constant and the ressure is decreased by 4.5 atm. On the phase diagram below draw a path that shows this set of changes. pressure (atm) 20 40 0 200 temperature (K) 400

Examine the nanoscale diagrams and the phase diagram for Question 112. Match each particulate diagram (1 through 7) to its corresponding point (A through H) on the phase diagram.

Suppose that three unknown pure substances are liquids at room temperature. You make vapor pressure measurements and find that substance Q has a pressure of torr, substance R has a pressure of 42 torr, and substance S has a pressure of 330 torr. If you slowly increase the temperature, which substance will boil first and which will boil last?

What term is used to describe a substance that readily evaporates at room temperature because of a high vapor pressure?

Chloroform, CHCl3, has a normal boiling point of 61C. Its vapor pressure at 43C is 0.526 atm. What is the concentration (in g/L) of CHCl3 when it saturates the air at 27C?

In each of the following groups of substances, pick the one that has the given property. Justify your answer. a. highest boiling point: HBr, Kr, or Cl2 b. highest freezing point: H2O, NaCl, or HF c. lowest vapor pressure at 25C: Cl2, Br2, or I2 d. lowest freezing point: N2, CO, or CO2 e. lowest boiling point: CH4, CH3CH3, or CH3CH2CH3 f. highest boiling point: HF, HCl, or HBr g.

Two molecules that contain the same number of each kind of atom but [hat have different molecular structures are said to he isomers of each other. For example, both ethyl alcohol and dimethyl ether (shown below} have the formula C2H6Oand are isomers; Based on considerations of intermolecular forces. which substance would you expect to be more volatile? Which would you expect 10have the higher boiling point? Explain. methyl ether hyl alcohol msp;CH3OCH3CH3CH2OH

A tank of gas at 21C has a pressure of 1.0 atm. Using the data in the table, answer the following questions. Explain your answers. a If the tank contains carbon tetrafluoride, CF4, is the liquid state also present? b If the tank contains butane, C4H20, is the liquid state also present?

A solution of benzoic acid in benzene has a freezing point of 3.1 C and a boiling point of 82.6 C. (The freezing point of pure benzene is 5.50 C, and its boiling point is 80.1 C) The structure of benzoic acid is Benzoic acid, C6H5CO2H What can you conclude about the state of the benzoic acid molecules at the two different temperatures? Recall the discussion of hydrogen bonding in Section 11.3.

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?