7. Classify as true or false-for a. For an insoluble salt, Ksp is always less th
ID: 549035 • Letter: 7
Question
7. Classify as true or false-for a. For an insoluble salt, Ksp is always less than 1 b. More PbClz can be dissolved at 100 °c than at 25C. statements rthe false statements, correct them so they are true : 25 oc. Therefore,t dissolving PbClz is likely endothermic. When sodium hydroxide is c. ded to a saturated solution of copper(l) hydroxide, the a saturat mass of copper(l) hydroxide present will decrease. 8. Marble is composed effect on m mostly of calcium carbonate. Acid rain can have a deleterious arble that is exposed to the weather. The reaction that occurs is: CaCO3 (s) + H. (aq) Ca2"(aq) + HCO' (aa) at is the equilibrium constant for this reaction? What is the molar solubility of Caco n water? What is the molar solubility of Caco, (s) in a solution of pH 4.00? 9. Which is more soluble in a basic solution than in pure water? A. Mg(OH)2 B. CaHPO4 C. NaCi D. CaCO3 E. Agl 10. A solution is made by combining 125 mL of 0.100 M AuNO, and 225 mL of 0.0490 M AgNOs. Then a sample of 25.0 mL of 0.0100 M HCI (aq) is added. When equilibrium is reached, will there be no precipitate, a precipitate of AuCi, a precipitate of AgCI, or a precipitate containing both AuCl and AgCI? 11. What is the solubility of CaF2 (s) in a buffer containing 0.30 M HCHO2 and 0.20 M NaCHO2? 12. A 1.0-L saturated silver carbonate solution at 5"C is filtered to remove undissolved solid and treated with enough hydrochloric acid to decompose the dissolved compound. The carbon dioxide generated is collected in a 19-ml vial and exerts a pressure of 114 mmHg at 25°C. What is the Kp of silver carbonate at 5*C? The number of moles of CO2 - moles Ag2CO3 dissolvedExplanation / Answer
7. a: True:
The Ksp values for insoluble salts are very low which are less than one.
7. b: True:
Endothermic reactions more favorable when heat energy supplied. Here we increase temperature and the solubility increases. So, the process of dissolving PbCl2 is endothermic.
7. c: False:
copper hydroxide solubility equilibrium: Cu(OH)2(s) <------> Cu2+ (aq) + 2 OH- (aq)
According to Le Chatelier's principle, addition of products to the equilibrium results the equilibrium shifted to left that is reactant side.
Since NaOH gives OH-, one of the product of above equilibrium, the solubility decreases. So, the mass of copper (II) hydroxide increases.
Correction: To decrease the mass of copper (II) hydroxide, add HCl.
Since HCl is acid, it reacts with OH- and decrease the hydroxide concentration means product concentration. So, the equilibrium shifted to right and more solid is dissolved and hence, mass of solid (copper (II) hydroxide) decreased.