Chapter 13 and 14 Chemistry Test Review

a. What is a saturated solution? b. What visible evidence indicates that a solution is saturated? c. What is an unsaturated solution?

1 A.) A solution in which the maximum amount of solvent has been dissolved 2 B.)If more solute is added to the solution and the solute remains undissolved, then you know that solution is saturated. 3 C.)An unsaturated solution is a chemical solution in which the solute concentration is lower than its equilibrium solubility.

a. What rule of thumb is useful for predicting whether one substance will dissolve in another? b. Describe what the rule means in terms of various combinations of polar and nonpolar solutes and solvents

1 The rule of thumb for predicting solubility is "like dissolves like". 2 In general, the rule means that polar substance dissolves in polar solvents while non-polar substances dissolve in non-polar solvents.

a. What is meant by the solubility of a substance? b. What condition(s) must be specified when expressing the solubility of a substance?

1 The solubility of a substance is the amount of that substance that is dissolved at solution equilibrium in a specific amount of solvent at a specified temperature. 2 The temperature and pressure (for gases) must be specified

a. How does pressure affect the solubility of a gas in a liquid? b. What law is a statement of this relationship? c. If the pressure of a gas above a liquid is increased, what happens to the amount of the gas that will dissolve in the liquid, if all other conditions remain constant? d. Two bottles of soda are opened. One is a cold bottle and the other is at room temperature. Which system would show more effervescence and why?

1 a. The solubility of a gas in a liquid is directly proportional to its pressure above the liquid. b. Henry's law 2 c. If the pressure above the gas increases, the amount of gas that can dissolve will increase. d. There will be more bubbles released from the partially frozen one. The gas molecules have less kinetic energy in the colder bottle and gases dissolve better in liquids at lower temperatures. Therefore they take up less volume; it is more difficult for them to escape from the solvent.

Under what circumstances might we prefer to express solution concentrations in terms of a. molarity? b. molality?

If you are making a solution by volume, use molarity(moles/liter). If you are weighing your ingredients, use molality (moles/1000g solvent).

Based on Figure 13-15, at what temperature would each of the following solubility levels be observed? a. 50 g KCl in 100 g H2O b. 100 g NaNO3 in 100 g H2O c. 60 g KNO3 in 100 g H2O

a) 38° C b) 36° C c) 32° C

What is the Tyndall effect? Identify one example of this effect.

a) It is the scattering of light by colloids and suspensions. b) The visibility of a headlight beam on a foggy night.

What is solution equilibrium? What factors determine the point at which a given solute-solvent combination reaches equilibrium?

a) Solution Equilibrium is the physical state in which the opposing processes of dissolution and crystalization of a solute occur at equal rates. b) The time to reach the equilibrium value depended on the drop size, solute, solvent, and temperature combination.

Given an unknown mixture consisting of two or more substances, explain how we could determine whether that mixture is a true solution, a colloid, or a suspension.

Pass the mixture through filter paper. The large particles in the suspension will filter out. Solution: homogeneous mixture of two or more substances in a single phase. Colloids: particles are intermediate in size between those in solutions and suspensions. To tell the difference between a solution and a colloid, shine a beam of light through the mixture, if it reflects then it is a colloid, if it doesn't then it is a solution

Based on Figure 13-15, determine the solubility of each of the following in grams of solute per 100. g H2O. a. NaNO3 at 10°C b. KNO3 at 60°C c. NaCl at 50°C

a.80g NaNO3 b.105g KNO3 c.40g NaCl

What opposing forces are at equilibrium in the sodium chloride system shown in Figure 13-7?

according to figure 7, the solute is recrystallizing at the same rate that it is dissolving. Therefore, recrystallizing and dissolving are two force in equilibrium.