The Standard Hydrogen Electrode The absolute value of a half cell potential cannot be measured, only differences in potential between pairs of half-cells. For this reason, it is necessary to have a...
Electrochemical Cells We have seen previously that?redox?reactions involve simultaneous?oxidation?and?reduction?as electrons flow from the?reducing agent?to the?oxidizing agent Which way electrons ...
Acid & Base Calculations pH The acidity of an aqueous solution depends on the number of?H3O+?ions in solution pH?is defined as: pH = -log [H3O+] Where [H3O+] is the concentration of?H3O+?ions i...
Acid & Base Dissociation Constants Weak acids A?weak acid?is an acid that?partially?(or incompletely)?dissociates?in aqueous solutions For example, most carboxylic acids (e.g. ethanoic acid), H...
Salt Hydrolysis An ionic salt is formed from the neutralisation reaction of an acid and base Neutralisation? The ionic salt, MA, formed will dissociate in water Hydrolysis?is where water is used to...
Buffers A?buffer solution?is a solution which resists changes in pH when small amounts of acid or base are added A buffer solution is used to keep the pH almost constant A buffer can consist of?wea...
Indicators An?acid-base?indicator?is a weak acid which dissociates to give an anion of a different colour Consider a weak acid, HIn: HIn (aq)? + H2O (l)? ? H3O+?(aq) + In–?(aq) colour 1? ? ? ? ? ? ...
pH Curves During a titration, a pH meter can be used and a pH curve plotted A pH curve is a graph showing how the pH of a solution changes as the acid (or base) is added The features of a pH curve ...
Lewis Theory of Acids & Bases A more general definition of acids and bases was given by G.N. Lewis who defined them as: A Lewis?acid?is an?electron pair acceptor A Lewis?base?is an?electron pai...
