C15 Analysis 0.0 / 5 ? ChemistryTesting and analysing substancesIGCSEAQA Created by: Lotto65Created on: 10-05-16 13:08 Give two ways to test for positive ions Flame test or with sodium hydroxide solution 1 of 39 How should the bunsen flame be with the flame test? Non-luminous 2 of 39 What colour does sodium go in the flame test? Yellow 3 of 39 What colour does barium go in the flame test? Apple green 4 of 39 What colour does calcium go in a flame test? Brick red 5 of 39 What colour does lithium go in the flame test? Crimson 6 of 39 What colour does potassium go in a flame test? Lilac 7 of 39 The hydroxides of metals with what charges are insoluble in water? 2+ and 3+ 8 of 39 Which ions all form white precipitates when in hydroxide form? Aluminium, magnesium and calcium 9 of 39 How can you tell which white precipitate is aluminium? Will dissolve in excess sodium hydroxide 10 of 39 How can you distinguish between magnesium and calcium precipitates? Flame test 11 of 39 What colour does magnesium turn in the flame test? No colour 12 of 39 What colour is the copper hydroxide precipitate? Blue 13 of 39 What colour is the iron(II) hydroxide precipitate? Green 14 of 39 What colour is the iron(III) hydroxide precipitate? Brown 15 of 39 How do you test for carbonate ions? Add hydrochloric acid to see if it fizzes, it if does test the gas with limewater to see if it goes cloudy 16 of 39 How do you test for halide ions? Add dilute nitric acid and then silver nitrate solution and see what colour the precipitate is 17 of 39 What colour is the precipitate of chloride ions? White 18 of 39 What colour is the precipitate of bromide ions? Cream 19 of 39 What colour is the precipitate of iodide ions? Yellow 20 of 39 How do you test for sulfate ions? Add dilute hydrochloric acid and barium chloride solution to see if white precipitate is formed 21 of 39 What is a mixture? 2 or more elements or compounds not chemically bonded together 22 of 39 What is filtration used for? Separate an insoluble substance from a solvent with soluble substances in 23 of 39 What is crystallisation used for? Separate a dissolved solid from a solution 24 of 39 What is distillation used for? Separate mixtures of miscible liquids with different boiling points or collect the solvent 25 of 39 What are miscible liquids? Liquids that dissolve in each other and do not form separate layers 26 of 39 What does paper chromatography analyse? The artificial colours in food or dyes in inks 27 of 39 Why do colours move different distances in chromatography? Depending on their solubility 28 of 39 How do you work out which substance is which from a chromatogram? Compare with other chromatograms of known substances taken at the same temperature with the same solvent 29 of 39 Give some benefits of modern instrumental methods Quicker, more sensitive, more accurate, tiny samples can be tested 30 of 39 What are some disadvantages of using modern instrumental methods? Expensive, special training needed, results can only be interpreted by comparison of data 31 of 39 Why would you use gas chromatography? Separate mixtures so they can be analysed and identified 32 of 39 How is a mixture carried through a column in gas chromatography? By a carrier gas that helps it through a colum packed with solid particles 33 of 39 How can you record retention times? The individual compounds travel at different speeds through the column and it records how much left the column in how long 34 of 39 How can you then identify compounds? Compare to results for known compounds 35 of 39 What does a mass spectrometer do? Quickly identifies individual compounds 36 of 39 How does a mass spectrometer work? Matches the compounds against the mass spectra of known substances 37 of 39 Where is the molecular ion peak found? Furthest peak on the right of the mass spectrum 38 of 39 What is the molecular ion peak? Shows the relative molecular mass of a substance where the individual compound with a large peak corresponds to an ion with one electron removed 39 of 39
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