The enthalpy of fusion of chlorine, Cl2, is 6.40 kJ/mol,

Most substances can be in three states.What are they?

Explain how solid naphthalene in mothballs is distributed evenly through clothes in a drawer.

What is the freezing point of a substance?

Carbon tetrachloride, CCl4, is nonpolar. What forces hold the molecules together?

Compare dipole-dipole forces and hydrogen bonds.

What is the difference between the terms state and phase?

Define boiling point in terms of vapor pressure.

What is a triple point?

Compare the arrangement and movement of particles in the solid, liquid, and gas states of matter.

What is surface tension?

A small drop of water assumes an almost spherical form on a Teflon surface. Explain why.

What is happening when water is heated from 25C to 155C?

Give an example of deposition.

Contrast ionic and molecular substances in terms of the types of attractive forces that govern their behavior.

Is the melting point of CaCl2 higher than that of NaCl or lower? Explain your answer.

A fellow student says, All substances experience London dispersion forces of attraction between particles. Is this statement true? Explain your answer.

Which has larger London dispersion forces between its molecules, CF4 or CCl4?

Of the three forces, ionic, dipole-dipole, and London dispersion forces, which is the strongest?

Why does ice float in water even though most solids sink in the pure liquid?

Why does CBr4 boil at a higher temperature than CCl4 does?

The molar enthalpy of fusion of water is 6.009 kJ/mol at 0C. Explain what this statement means.

Why is the molar enthalpy of vaporization of a substance much higher than the molar enthalpy of fusion?

How do you calculate the entropy change during a change of state at equilibrium?

Why is the entropy of a substance higher in the liquid state than in the solid state?

At 100C, the enthalpy change for condensation of water vapor to liquid is negative. Is the entropy change positive, or is it negative?

H for a process is positive, and S is negative.What can you conclude about the process?

Explain why liquid water at 273.0 K will not melt in terms of Gibbs energy.

at thermodynamic values do you need to know to calculate a substances melting point?

How does pressure affect the entropy of a gas?

How does pressure affect changes between the liquid and vapor states?

You have sweetened iced tea with sugar, and ice cubes are present. How many phases are present?

The term vapor pressure almost always means the equilibrium vapor pressure.What physical arrangement is needed to measure vapor pressure?

What is meant by the statement that a liquid and its vapor in a closed container are in a state of equilibrium?

As the temperature of a liquid increases, what happens to the vapor pressure?

Use the above graph of the vapor pressure of water versus temperature to answer the following questions. a. At what point(s) does water boil at standard atmospheric pressure? b. At what point(s) is water only in the liquid phase? c. At what point(s) is water only in the vapor phase? d. At what point(s) is liquid water in equilibrium with water vapor?

What two fixed points are on all phase diagrams?

The enthalpy of fusion of chlorine, Cl2, is 6.40 kJ/mol, and the entropy of fusion is 37.2 J/molK.

The enthalpy of fusion of sulfur trioxide is 8.60 kJ/mol, and the entropy of fusion is 29.7 J/molK.

The enthalpy of vaporization of butane, C4H10, is 22.44 kJ/mol, and the entropy of vaporization is 82.2 J/molK.

Hvap for silicon tetrachloride is 28.7 kJ/mol, and Svap is 86.7 J/molK.

The critical point for krypton is at 64C and a pressure of 5.5 103 kPa.The triple point is at 157.4C and a pressure of 73.2 kPa. At 172C, the vapor pressure is 13 kPa.The normal boiling point is 152C. Sketch the phase diagram.

The critical point for carbon tetrachloride is at 283C and 4.5 103 kPa.The triple point is at 87.0C and 28.9 kPa.The normal boiling point is 76.7C. Sketch the phase diagram.

Calculate the melting point of acetic acid at standard pressure.The enthalpy of fusion of acetic acid is 11.54 kJ/mol, and the entropy of fusion is 39.8 J/molK.

Hvap for gold is 324 kJ/mol, and Svap is 103.5 J/molK. Calculate the boiling point of gold.

The critical point for HBr is at 90C and 8.56 103 kPa.The triple point is at 87.0C and 29 kPa.The normal boiling point is 66.5C. Sketch the phase diagram.

How can water be made to evaporate rapidly at room temperature?

How does a pressure cooker work?

Which would have the higher boiling point: chloroform, CHCl3, or bromoform, CHBr3?

You know that the enthalpy change for vaporizing water is Hvap = Hgas Hliq. What is the Gibbs energy change for this process?

Explain why steam produces much more severe burns than the same amount of boiling water does.

Chloroethane (Tbp = 13C) has been used as a local anesthetic.When the liquid is sprayed onto the skin, it cools the skin enough to freeze and numb the skin. Explain the cooling effect of this liquid.

Is it possible to have only liquid water present in a container at 0.00C? Explain.

Consider a system composed of water vapor and liquid at equilibrium at 100C. Do the molecules of H2O in the vapor have more kinetic energy than molecules in the liquid do? Explain.

Look at the phase diagram for carbon dioxide. How can CO2 be made to boil?

Liquid crystals are substances that have properties of both liquids and crystals. Write a report on these substances and their various uses.

Some liquids lose all viscosity when cooled to extremely low temperaturesa phenomenon called superfluidity. Find out more about the properties of superfluid substances.

Many scientists think that more than 99% of the known matter in the universe is made of a fourth state of matter called plasma. Research plasmas, and report your findings to the class.

Prepare a report about the adjustments that must be made when cooking and baking at high elevations. Collect instructions for highelevation adjustments from packages of prepared food mixes. Explain why changes must be made in recipes that will be prepared at high elevations. Check your library for cookbooks that contain information about food preparation at high elevations.

Use the following terms to create a concept map: boiling point, liquids, vapor pressure, gases, melting point, states, and equilibrium

What is the normal boiling point of water?

Give the coordinates for a point at which only liquid water is present.

Give the coordinates for a point at which liquid water is in equilibrium with vapor.

Give the coordinates for a point at which only vapor is present.

What is the vapor pressure of water at point E?

What will happen if the vapor at point D is cooled at constant pressure?

Graphing Calculator Calculating Vapor Pressure by Using a Table The graphing calculator can run a program that calculates a table for the vapor pressure in atmospheres at different temperatures (K) given the number of moles of a gas and the volume of the gas (V). Given a 0.50 mol gas sample with a volume of 10 L, you can calculate the pressure at 290 K by using a table. Use this program to make the table. Next, use the table to perform the calculations. Go to Appendix C. If you are using a TI-83 Plus, you can download the program VAPOR and data and run the application as directed. If you are using another calculator, your teacher will provide you with keystrokes and data sets to use. After you have run the program, answer the questions. a. What is the pressure for 1.3 mol of a gas with a volume of 8.0 L and a temperature of 320 K? b. What is the pressure for 1.5 mol of a gas with a volume of 10.0 L and a temperature of 340 K? c. Two gases are measured at 300 K. One has an amount of 1.3 mol and a volume of 7.5 L, and the other has an amount of 0.5 mol and a volume of 10.0 L.Which gas has the lesser pressure?