BRAINCAKEChemical changes
Revision notes for Chemical changes in AQA Chemistry (8462). Every lesson in BrainCake comes with R.E.C.I.P.E. recall steps, a quick check and spaced reviews.
- Metal oxidesMetals react with oxygen to make metal oxides.
- The reactivity seriesWhen metals react, their atoms lose electrons and form positive ions.
- Extraction of metals and reductionVery unreactive metals such as gold are found in the Earth as the metal itself.
- Oxidation and reduction in terms of electrons (HT only)Oxidation and reduction can also be described using electrons.
- Reactions of acids with metalsAcids react with some metals to produce a salt and hydrogen.
- Neutralisation of acids and salt productionAn acid is neutralised by an alkali or a base.
- Soluble saltsSoluble salts can be made by reacting an acid with an insoluble solid: a metal, a metal oxide, a metal hydroxide or a metal carbonate.
- The pH scale and neutralisationAcids produce hydrogen ions (H+) in aqueous solution.
- Titrations (chemistry only)A titration measures the volumes of an acid solution and an alkali solution that react exactly with each other.
- Strong and weak acids (HT only)A strong acid is completely ionised in aqueous solution.
- The process of electrolysisSolid ionic compounds do not conduct electricity because their ions are held in fixed positions.
- Electrolysis of molten ionic compoundsSolid lead bromide, PbBr2, does not conduct electricity, but when it is heated until it is molten its ions are free to move and it can be…
- Using electrolysis to extract metalsMetals can be extracted from their molten compounds by electrolysis.
- Electrolysis of aqueous solutionsAn aqueous solution contains the dissolved ionic compound and also water.
- Representation of reactions at electrodes as half equations (HT only)During electrolysis, positively charged ions move to the cathode and gain electrons.