Quick Revision notes V2.0 Science Chem (No organic)

‘O’ Level Science Chemistry By Hazel You Quick Revision Notes V2.0 http://www.thekimiyagroup.com 1 ‘O’ Level Science Chemistry Quick Revision Notes • To check purity of a substance – Determine melting or boiling points (the only method) Common Chemicals Common Name Chemical Name Common Name Chemical Name Limestone Calcium carbonate Lime / quick lime Calcium oxide Limewater Calcium hydroxide Aqueous Ammonia Ammonium hydroxide Colour of some substances Colour Substances Colour Substances White Group I, II and III, ammonium compounds, Anhydrous CuSO4 Black CuO (s), I2 (s) Shiny/grey Most metals Yellow PbI, AgI, hot ZnO, Fe3+ (aq) Blue Cu2+ salts Red-brown Br2(l), Copper Metal, Fe(OH)3 (s) Green Fe(OH)2 (s), some Cu2+ salts Fe2+ (aq), Cr3+ 1. Separation techniques Method Substance to separate Substance(s) obtained Concept behind method Remarks Filtration § Insoluble solid from a liquid. § Soluble solid & insoluble solid Filtrate Residue (Solid) § Different solubility in the liquid § Large insoluble solid trapped by filter paper Decanting Large insoluble solid from liquid. - § Large insoluble solid - Evaporate to dryness A soluble solid from a liquid. Dry / anhydrous salt § Different physical states § Not for solids that decompose on heating Crystallisation § A pure solid from an impure solid. § A soluble solid from a liquid. § Substances which decompose. Well-formed crystals of the pure solid (solute) § As temperature decreases, solubility decreases. § When saturated solution is cooled, crystals are formed. § For solids that decompose on heating § To retain water of crystallisation (hydrated salt) Sublimation A mixture of solids which one of them sublimes. Pure solid which sublimes. § One substance changes directly from solid to vapour on heating. § E.g. iodine, moth balls, dry ice. Simple distillation A solution of a dissolved solid (solute) in a liquid. Pure liquid as distillate. § Different physical states § Liquid is heated into vapour, cools and condenses into pure liquid in condenser and collected as distillate. Fractional distillation Mixture of miscible liquids Pure liquids as distillate. § Difference in boiling point § Uses a fractionating column. § Liquid with the lower bp will be distilled out first. Separating funnel Mixture of two immiscible liquids. Two separated liquids § Difference in densities § Mixture separates into two layers Paper chromatography Solution containing mixture of small amounts of solids Solutes separated in the chromatogram. § Different solubility of solutes in the solvent used § More soluble solutes travel a longer distance with solvent.

‘O’ Level Science Chemistry By Hazel You Quick Revision Notes V2.0 http://www.thekimiyagroup.com 2 2. Particulate Nature of Matter • Kinetic Particle Theory of Matter – Particles ar