The equilibrium concentration of chromate ion in a saturated lead chromate solution is M. (Assume that Kp (PbCrO4) = 1.8 × 10-¹4.)

The following question is taken from a Chemistry Advanced Placement Examination and is used with the permission of the Educational Testing Service. Solve the following problem: MgF2(s)Mg2+(aq)+2F(aq) In a saturated solution of MgF2 at 18 C, the concentration of Mg2+ is 1.21103M . The equilibrium is represented by the preceding equation. (a) Write the expression for the solubility-product constant, Ksp, and calculate its value at 18 C. (b) Calculate the equilibrium concentration of Mg2+ in 1.000 L of saturated MgF2 solution at 18 C to which 0.100 mol of solid KF has been added. The KF dissolves completely. Assume the volume change is negligible. (c) Predict whether a precipitate of MgF2 will form when 100.0 mL of a 3.00103 -M solution of Mg(NO3)2 is mixed with 200.0 mL of a .2.00103 -M solution of NaF at 18 C. Show the calculations to support your prediction.. (d) At 27 C the concentration of Mg2+ in a saturated solution of MgF2 is 1.17103M . Is the dissolving of MgF2 in water all endothermic or an exothermic process? Give an explanation to support your conclusion.

Given that the Gf for Pb2+(aq) and Cl-(aq) is -24.3 kJ/mole and -131.2 kJ/mole respectively, determine the solubility product, Ksp, for PbCl2(s).

Write the expression of the reaction quotient for the ionization of HOCN in water.

In a particular experiment, the equilibrium constant measured for the reaction, Cl2(g)+NO2(g)Cl2NO2(g), is 2.8. Based on this measurement, calculate AG° for this reaction. Calculate AG° using data from Appendix E at the back of the book and discuss the agreement between your two calculations.

Some barium chloride is added to a solution that contains both K2SO4 (0.050 M) and Na3PO4 (0.020 M). (a) Which begins to precipitate first: the barium sulfate or the barium phosphate? (b) The concentration of the first anion species to precipitate, either the sulfate or phosphate, decreases as the precipitate forms. What is the concentration of the first species when the second begins to precipitate?

. Lead(II) chloride, PbCl2(s), dissolves in water to the extent of approximately 3.6102Mat 20 °C. Calculate Kspfor PbCl2(s), and calculate its solubility in grams per liter.

Because calcium carbonate is a sink for CO32- in a lake, the student in Exercise 12.39 decides to go a step further and examine the equilibrium between carbonate ion and CaCOj. The reaction is Ca2+(aq) + COj2_(aq) ** CaCO,(s) The equilibrium constant for this reaction is 2.1 X 10*. If the initial calcium ion concentration is 0.02 AI and the carbonate concentration is 0.03 AI, what are the equilibrium concentrations of the ions? A student is simulating the carbonic acid—hydrogen carbonate equilibrium in a lake: H2COj(aq) H+(aq) + HCO}‘(aq) K = 4.4 X 10"7 She starts with 0.1000 AI carbonic acid. What are the concentrations of all species at equilibrium?

Because barium sulfate is opaque to X-rays, it is suspended in water and taken internally to make the gastrointestinal tract visible in an X-ray photograph. Although barium ion is quite toxic, barium sulfate’s /Csp of 1.1 X 10-,<) gives it such low solubility' that it can be safely consumed. What is the molar solubility' of BaSO4. What is its solubility' in grams per 100 g of water?

Magnesite (magnesium carbonate, MgCO3) is a common magnesium mineral. From the solubility product constant, find the solubility of magnesium carbonate in grams per liter of water.