test 2 revision

• acid buffers contain a mixture of a weak acid and it's conjugate base
• basic buffers contain a mixture of a weak base and it's conjugate acid
• buffer solutions are solutions that resist a change in pH when small amounts of acid or base are added
• buffer capacity: how much added acid / base a buffer system can absorb before a change in pH occurs
• acidic buffer system example: ethanoic acid / sodium ethanoate
• basic buffer system example: ammonia / ammonium chloride
• oxidation: reactant ----> product + electrons
• reduction: reactant + electrons -------> product
• oxidation number of oxygen: -2 unless in a peroxide molecule, then it's +2
• oxidation number of monatomic ions: charge of the ion from periodic table
• oxidation number of hydrogen: +1 excpet metal hydrides where it's -1
• oxidation number of atoms of elements in the elemental state: 0 (e.g Zn(s))
• elements exhibit a range of oxidation numbers due to their electron arrangement
• oxidation = increase in oxidation number
• reduction: decrease in oxidation number