solutions

7 rules of solubility

1. all salts containing ammonium (NH4+) and alkali metals (Group 1) cations are water soluble

2. all salts containing Nitrate (NO3-) and acetate (CH3COO-) anions are water soluble

3. Halides (Cl-, Br-, I-) excluding fluorides are water soluble, with the exception of those formed with Ag+2, Sr+2, Ba+2, Pb+2

4. All salts of sulfate ion (SO4-2) are water soluble with the exception of those formed with Ca+2, Sr+2, Ba+2, and Pb+2

5. all metal oxides are insoluble with the exception of those formed with the alkali metals, ammonium, and CaO, SrO, and BaO, all of which hydrolyze to form solutions of the corresponding metal hydroxides

6. all hydroxides are insoluble with the exception of those formed with the alkali metals, ammonium, and Ca+2, Sr+2, and Ba+2

7. all carbonates (CO3-2), phosphates (PO4-3), sulfides (S-2), and sulfites (SO3-2) are insoluble with the exception of those formed with the alkali metals and ammonium

complex ion

molecule in which a cation is bonded to at least one electron pair donor (which could include the water molecule)

ligand

electron pair donor molecules

Molarity (M)

moles of solute/ liters of solution

Molality (m)

moles of solute / kilograms of solvent

solubility product constant (K_sp)

A_mB_n (s) ⇌ mAⁿ⁺ (aq) + nB^m- (aq)

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K_sp = [Aⁿ⁺]^m + [B^m-]ⁿ

ion product (IP)

analogous to the reaction quotient Q

determine where the system is with respect to the equilibrium position

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IP = [Aⁿ⁺]^m + [B^m-]ⁿ

IP vs K_sp

IP < K_sp = unsaturated; solution will continue to dissolve

IP = K_sp = saturated; solution at equilibrium

IP > K_sp = supersaturated; solution will precipitate

common ion effect

reduction in molar solubility

Boiling Point elevation

ΔT_b = i K_b m

i = van’t Hoff Factor

m = molality of the solution

K_b = proportionality constant characterisitic to a particuar solution

Freezing Point depression

ΔT_f = i K_f m

i = van’t Hoff Factor

m = molality of the solution

K_f = proportionality constant characterisitic to a particuar solution

osmotic pressure

pressure generated by solution in which water is drawn into a solution

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Π = i MRT

i = van;t Hoff factor

M = molarity

R = ideal gas constant

T = temperature