Acids and Bases 2 - Summary PDF

GAS LAWS ph The pH of a solution is defined as the negative logarithm to the base 10 of the hydrogen ion concentration. Limitations The pH scale is not useful outside the 0-14 range. The pH scale is limited to aqueous solutions. Self-Ionisation of WATER Water reacts with itself as follows: H₂O + H₂O...

GAS LAWS ph The pH of a solution is defined as the negative logarithm to the base 10 of the hydrogen ion concentration. Limitations The pH scale is not useful outside the 0-14 range. The pH scale is limited to aqueous solutions. Self-Ionisation of WATER Water reacts with itself as follows: H₂O + H₂O ⇋ H₃O⁺ + OH⁻ At 298K, Kw (the dissociation constant of water) is: Kw = [H₃O⁺][OH⁻] = 1 x 10⁻¹⁴ In pure water (pH is exactly 7), H₃O⁺ & OH⁻ ACIDS ions are present in the same concentrations ∴ [H₃O⁺ ] = [OH⁻] = 1 x 10⁻⁷ at 298K pH = -log₁₀ [H₃O⁺] Weak Acid [H30+] = pH = -log₁₀ [H₃O⁺] BASES pH = 14 - pOH pOH = -log [OH-] Weak Base [OH-] = pOH = -log [OH-] pH = 14 - pOH Indicator: Metyl Orange pH range: 3-5 Acid colour: Red Base colour: Yellow (note: an intermediate peach pink is the end point of a titration with methyl orange) Indicator: Phenolphthalein pH range: 8-10 Acid colour: Colourless Base colour: Pink Acids and Bases 2 TITRATION CURVES