Chapter 16, Problem 3P

The ore cinnabar (HgS) is an important source of mercury. Cinnabar is a red solid whose solubility in water is 5.5 X 10-2 mol L-1. Calculate its \p. What is its solubility' in grams per 100 g of water?

Consider a metal ion A2+ and its nitrate salt, In an experiment, 35.00 mL of a 0.217 M solution of A(NO3)2 is made to react with 25.00 mL of 0.195 M NaOH. A precipitate, A(OH)2, forms. Along with the precipitation, the temperature increases from 24.8C to 28.2C. What is H for the precipitation of A(OH)2? The following assumptions can be made. • The density of the solution is 1.00 g/mL. • Volumes are additive. • The specific heat of the solution is 4.18 J/g C.

The following is a thought experiment. Imagine that you put a little water in a test tube and add some NaF crystals. Immediately after you add NaF, you observe that the crystals begin dissolving. The quantity of solid NaF decreases, hut before long, it appears that no more NaF is dissolving. The solution is saturated. The equation for the dissolution of NaF in water is NaF(s) —* Na (aq) + F~(aq). As NaF dissolves, what do you think happens to the rate of dissolution? Describe w hat is occurring on the molecular level. Assume that the reverse reaction, Na+(aq) + F“(aq) —* NaF(s), also occurs as the crystal dissolves. In other words, both dissolution and precipitation are taking place. When it appears that there is no more change in the quantin’ of NaF dissolving (the solution is saturated), w hat has happened to the rates of the forward and reverse reactions? Explain your answer.

5.2. What is the difference between a static equilibrium and a dynamic equilibrium? Give examples difference from the examples in the text. What is similar for the two types of equilibria?

Show that the complete chemical equation, the total ionic equation, and the net ionic equation for the reaction represented by the equation KI(aq)+I2(aq)KI3(aq) give the same expression for the reaction quotient. KI3 is composed of the ions K+ and I3-.

In Section 13.1 of your text, it is mentioned that equilibrium is reached in a closed system. What is meant by the term closed system. and why is it necessary to have a closed system in order for a system to reach equilibrium? Explain why equilibrium is not reached in an open system.

In Section 17.3 of your text, it is mentioned that equilibrium is reached in a closed system. What is meant by the term “closed system,” and why is it necessary for a system to reach equilibrium? Explain why equilibrium is not reached in an open system.

Dissolving CaCO3 is an endothermic reaction. The following five graphs represent an experiment done on CaCO3. Match the experiment to the graph. (a) HCl is added. (b) The temperature is increased. (c) CaCl2 is added. (d) NaCl is added.

12.85 In the figure, orange fish are placed in one aquarium and green fish in an adjoining aquarium. The two tanks are separated by a removable partition that is initially closed. Describe what happens in the first few minutes after the partition is opened. WTiat would you expect to see several hours later? How is this system analogous to dynamic chemical equilibrium?