chemistry 112 exam 3

chemical equliibrium

rate of forward reaction equals rate of reverse reaction

dynamic process

temperature dependent

equilibrium constant

Kc or Kp

relates molar concentrations of the products and reactants after the equilibrium has been reached

only include aqueous solutions and gases (not solids and liquids)

for Kp, use partial pressures

equilibrium constant evaluation

Kc > 1: reaction goes to completion, favors products

Kc < 1: no reaction, favors reactants

Kc value for reverse reactions

and vice versa

how to add reaction Kc

multiplying reactions K

(A+B = C+D) x (A+B = C+D) : K = (K1)²

how to compare Kp and Kc

if change in n = 0, Kp = Kc

ICE table

for solving equilibrium calculations

I: initial concentrations

C: change (+ for amount generated, - for amount used)

E: equilibrium concentrations

PAY ATTENTION TO STOICHIOMETRY FROM EQUATION

reaction quotient

Qc and Qp

predicts which direction the reaction will proceed

calculated like equilibirum constant

for concentrations not at equilibrium

reaction quotient analysis

Qc < Kc: reactions converted to products, forward reaction

Qc = Kc: system is at equilibrium

Qc > Kc: products converted to reactants, reverse reaction

le chatelier’s principle

reactions respond to change to minimize the change and reestablish equilibrium

temperature change: shift based on endothermic and exothermic reactions (if exothermic, moves towards reactants)

concentration change: high concentration of reactants, more products made and vice versa

volume/pressure change: shift based on # of gaseous moles (if pressure increased, moves to side with less moles) (if pressure decreased, moves to side with more moles)

arrhenius definitions of acid/base

acid: produced H+ in solution

base: produces OH- in solutions

bronsted lowry definitions of acid/base

acid: proton donor

base: proton acceptor

lewis definition of acid/base

acid: electron pair acceptor

base: electron pair donor

conjugate acid-base pair

acid and corresponding base on other side

base and corresponding acid on other side

strong acids and bases

acids: HCl, HI, HBr, HClO4, HNO3, H2SO4 (dissociate 100% in water) (Ka > 1)

base: LiOH, NaOH, KOH, Ca(OH)2, Sr(OH)2, Ba(OH)2

ion-product constant

Kw

Kw = 1.0 × 10^-14 (at room temp, 25°C)

14 = pH + pOH

pH and pOH

small pH = acidic (<7)

large pH = basic (>7)

pH = -log([H⁺]) AND [H+] = 10^-pH

pOH = -log([OH^-]) AND [OH-] = 10^-pOH

weak acids

dissociate less than 100%

any acid that isn’t strong

Ka < 1

% ionization

only for weak acids

( [H+] / [acid or base(initial)] ) x 100

acid dissociation/base protonation constant

Ka/Kb

HA(aq) + H₂O(l) ⇌ H₃O⁺(aq) + A^-(aq)

K_a = [H₃O⁺][A^-] / [HA]

can determine pH of weak acid solution or pOH of weak base solution from this using ICE table

large Ka = strong acid

small Ka = weak acid

weak bases

react less than 100%

any base not listed as strong

EX: NH3, OH-, HCOO-, CH3COO-

acid-base reaction (neutralization rxn)

acid (aq) and base (aq) combine to create a salt (aq) and water (l)

ionization reaction

HA = H+ + A-

EX: HCOOH = HCOO- + H+

oxyacid strength

oxyacid: X - O - H

higher oxidation # or higher # of O’s = stronger oxyacid