University:
Concordia University Wisconsin
Course:
CHEM 1414 | General Chemistry I
Academic year:

2020
Views:

281

Pages:

4
Author:

Accinkiquicpqw

Chemistry UNIT 3 SOLUTIONS AND SOLUBILITY SOLUBILITY: CHAPTER 8 Solubility can be conveyed or defined in many ways: • the maximum amount of substance which will dissolve to form one litre of solution. • a fixed amount of solute dissolved in a solution at equilibrium • amount of solute that saturates a solution Solubility is expressed in MOLARITY units (moles / L) The generally accepted values at RTP conditions, (which we call “standard state conditions”) as listed in your CHEM 12 DATA BOOKLET: s > 0.1 M is defined as “soluble” 0.001 M < s < 0.1 M is defined as “slightly soluble” s < 0.001 M is defined as “Insoluble” SOLUBILITY PRODUCT CONSTANT is represented as: Ksp Ksp can be defined in several ways: • • a constant number at a particular temperature as determined by the product (multiplication) of the ion concentrations raised to the power equal to the coefficients of the dissociation equation equilibrium constant for an ionic compound dissociation in water DISSOCIATION EQUATIONS Ksp expression AgCl (s) ⇄ Ag+ (aq) + Cl- (aq) Ksp = [Ag+] [Cl-] Ag2SO4 (s) ⇄ 2Ag+(aq) + SO4-2(aq) Ksp = [Ag+]2 [SO4-2] Ca3(PO4)2 (s) ⇄ 3Ca+2(aq) + 2PO4-3(aq) Ksp = [Ca+2]3 [PO4-3] 2 FeCl3 (s) ⇄ Fe+3(aq) + 3Cl-(aq) Ksp = [Fe+3] [Cl-]3 CuCl (s) ⇄ Cu+1(aq) + Cl-(aq) Ksp = [Cu+1] [Cl-1] RELATING SOLUBILITY AND SOLUBILITY PRODUCT CONSTANT: If “s” moles of solid Silver Chloride is dissolved to make a saturated 1.0 L solution, AgCl AgCl (s) “s” moles in 1.0 L ⇄ Ag+ + sM - - Ksp = [Ag+][ Cl ] = (s) (s) = s2 Cl sM Ag2S Al(OH)3 Al2(CO3)3 SUMMARY of Ksp EXPRESSIONS: FORMULA Ksp Expression A1B1 A1B2 A2B3 A1B3 AmBn s2 EXTRA PRACTICE (Applying the Ksp summary) Write the solubility product expressions for: AgBr Ag2SO4 Pb(OH)3 Hg2SO4 Al2(SO4)3 Characteristics of Ksp and Solubility: Ksp s Solubility Product Solubility Unitless UNITS: M = moles/L or kmol / m3 Refers to the "ions" (products) Relates to the solute (reactant) eg. Ksp = [Al ][ OH-] +3 3 eg. 1.5 X 10- moles of Al(OH)3 5 Ksp = f(s) dependent variable independent variable Ksp = (mm) (nn) (sm+n) A m Bn Used for ranking product preference Used for ranking solubility DEFINITIONS you can find IN SECTION 8.1 OF THE TEXT: IMPORTANT Solubility TERMS that you should be familiar with (so far)… Solution Solvent Solute Soluble Insoluble Solubility Miscible Immiscible Amalgams AIR Metal Alloys Supersaturated CALCULATIONS 1. The solubility of silver bromide is found to be 8.8 x 10-7 mol / L . Calculate the Ksp value for silver bromide. 2. The solubility of iron (II) hydroxide = 1.5 x 10-3 g/L. What is the Ksp value? 3. Calculate the solubility of calcium carbonate in water at 25oC. Use your data booklet for the Ksp value. 4. What mass of calcium phosphate solute will be needed to make a saturated 5.00 L solution of if Ksp = 4.8 x 10-25 ?