Acids and Bases and Equilbirium

• Concentration can only be accurately found by titration.
• E.g. HCL, NAOH

Accurately known concentration

Must be:

• In pure form consistant with chemical formula
• Stable upon exposure to air
• High molar mass

e.g. oxalic acid

Both react, depends on Kb>Ka, or Ka>Kb

• Cation of weak base reacts
• pH<7
• Acidic

• Anion of weak base reacts (hydrolyses)
• pH>7
• Basic

• Forming of an acid/base by water molecules and an ion
• Ions of strong acids/bases do not hydrolyse

• no hydrolyses
• pH=7
• Neutral

Anions that are conjugate bases of weak acids are basic

• F^-, CO₃^2- PO₄^3- CH₃COO^- 
• Organics

Cations that are conjugate acids of weak bases are acidic

NH₄⁺ Al³⁺ Mg²⁺

Transition metals

Anions: Cl^- Br^- I^- ClO₄^- SO₄^2-


Cations: Li⁺ Na⁺ K⁺ Rb⁺ Sr²⁺ Ba²⁺

• In any sample of water, some H2O molecules change into H+(aq) and OH-(aq) ions.
• They have the same concentration as they form at the same rater
• Water is neutral
• [H+]=1x10^-7
• [OH-]=1x10^-7

weak

Acid + Conjugate base (donates H+)

Base + Conjugate acid (accepts H+)

Acid donates a proton H+

Base accepts a proton H+

Acids produce hydrogen ions


Bases produce hydroxide ions

Reaction that absorbs heat is favoured

Rise in temp = favours endo

Decrease in temp = favours exo

Increase in pressure = Shift in the direction with the fewest moles of gas

Substance added: Shift to remove it

Substance removed: Shift to produce it

Tells us if the reaction is at equilibrium

• Q=K: equilibrium
• Q>K: Too much product
• Q<K: Too much reactants

Tells us how much product can be made before equilibrium is reached

K=[Products]/[Reactants]

• K>1 = forward rxn favoured
• K<1 = reverse rxn favoured