pH Scale: Uses negative logarithm of powers of 10. More manageable scale.
H Ion Concentration: Low value of [H+ (aq)] = high value of pH. A change in one pH number is
10x the [H+ (aq)].
Measuring pH: The electrode in pH meter measures electrical potential of H+ ions.
pH = – log[H+ (aq)]
[H+ (aq)] = 10-pH
Strong acid nothing to do with pH but with extent of dissociation. pH relates to concentration of
H+- the amount of solute, in moles, dissolved in 1dm3 of solution.
Strong Acid: [H+ (aq)] = [HA (aq)].
Changes to Dilution: Doubling volume = concentration halved as solution more diluted.
gdm-3: Mass/ Mr = moles. So will get moldm-3 which is concentration, so do as normal. Use Mr
of acid or base.
2 SF for pH values is 2.62 and not 2.6, as negative logarithm. Start counting SF for pH values after
decimal point like DP.
