Chemical Analysis 0.0 / 5 ? ChemistryAnalysing substancesGCSEAQA Created by: vickieboadiCreated on: 24-10-18 13:46 what is a pure substance it is a single element or compound, not mixed with any other substances 1 of 19 examples of pure substances oxygen, water, sodium chloride 2 of 19 examples of impure substances air, brine,milk 3 of 19 what is a formulation a mixture that has been designed as a useful product 4 of 19 examples of formulations lotions, medicines, fertilisers, food, fuel, paints cleaning agents 5 of 19 what is the test for hydrogen a lit splint will produce a squeaky pop 6 of 19 what is the test for oxygen a glowing splint will relight in the presence of oxygen 7 of 19 what is the test for carbon dioxide if you bubble carbon dioxide into limewater it will go from colourless to cloudy white - Ca(OH)2 + CO2 --> CaCO3 + H2O 8 of 19 what is the test for chlorine damp blue litmus will turn red then bleaches 9 of 19 how do we calculate the Rf value in chromatography Rf = distance moved by substance/ distance moved by solvent 10 of 19 How do we test for cations the flame test - nichrome wire 11 of 19 what cations are we testing for in the flame test Lithium (Li), Sodium(Na), Potassium(K), Copper(Cu), Calcium(Ca) 12 of 19 what colour is the flame they produce Li - crimson red, Na - yellow, K - lilac, Cu - green, Ca - brick red/orange 13 of 19 what do we test for aluminium, magnesium and calcium we use sodium hydroxide because aluminium will dissolve in excess sodium hydroxide. 14 of 19 what compounds form a coloured precipitated in sodium hydroxide Copper(ii)- blue precipitate, Iron(ii)- green precipitate, Iron(iii)-brown precipitate 15 of 19 what test do you use to identify chloride , bromide and iodide you use the halide test - add compound to silver nitrate - chloride - white precipitate, bromide - cream precipitate, iodide - yellow precipitate 16 of 19 what is the test for sulphates sulphate ions in solution produce a white precipitate with Barium chloride in presence of HCl 17 of 19 what are the advantages of the instrumental method more accurate, more sensitive, more rapid, able to test much smaller samples 18 of 19 what are the disadvantages of the instrumental method expensive complex, - special training needed, comparison with known data 19 of 19
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