Chemical analysis

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Sample objectives

What this unit covers

• Purity, formulations and chromatography: Use melting point data to identify a pure substance.
• Purity, formulations and chromatography: Define a pure substance in chemistry as a single element or compound not mixed with any other substance.
• Purity, formulations and chromatography: Explain that each component in a formulation contributes to the properties of the product.
• Purity, formulations and chromatography: Explain that formulations are made by mixing components in carefully measured quantities.
• Purity, formulations and chromatography: Explain that separation depends on the distribution of substances between the mobile phase and the stationary phase.
• Purity, formulations and chromatography: Explain that a mixture may produce more than one spot on a chromatogram.
• Identification of common gases: Describe the test for hydrogen using a lighted splint.
• Identification of common gases: Recall that hydrogen burns with a squeaky pop.
• Identification of common gases: Interpret a glowing splint relighting as evidence that oxygen is present.
• Identification of common gases: Distinguish the oxygen test from tests for hydrogen, carbon dioxide and chlorine.
• Identification of common gases: Describe the test for carbon dioxide using limewater.
• Identification of common gases: Interpret limewater turning milky as evidence that carbon dioxide is present.
• Identification of common gases: Recall that chlorine bleaches damp litmus paper.
• Identification of common gases: Describe the test for chlorine using damp litmus paper.
• Identification of ions by chemical and spectroscopic means: Recall that calcium ions produce an orange-red flame.
• Identification of ions by chemical and spectroscopic means: Interpret flame colour observations to identify metal ions.
• Identification of ions by chemical and spectroscopic means: Describe how sodium hydroxide solution can be used to test for some metal ions.
• Identification of ions by chemical and spectroscopic means: Recall that aluminium ions form a white precipitate that dissolves in excess sodium hydroxide.
• Identification of ions by chemical and spectroscopic means: Recall that limewater turns milky if carbon dioxide is produced.
• Identification of ions by chemical and spectroscopic means: Carry out the carbonate ion test safely. (AT 8)
• Identification of ions by chemical and spectroscopic means: Distinguish the sulfate ion test from carbonate and halide ion tests.
• Identification of ions by chemical and spectroscopic means: Recall that sulfate ions produce a white precipitate of barium sulfate.
• Identification of ions by chemical and spectroscopic means: Recall that bromide ions produce a cream precipitate.
• Identification of ions by chemical and spectroscopic means: Recall that chloride ions produce a white precipitate.
• Identification of ions by chemical and spectroscopic means: Use flame tests to identify metal ions in unknown compounds.
• Identification of ions by chemical and spectroscopic means: Plan a sequence of tests to identify ions in an unknown compound.
• Identification of ions by chemical and spectroscopic means: Explain that flame emission spectroscopy can identify metal ions from a line spectrum.
• Identification of ions by chemical and spectroscopic means: Explain that the intensity of lines in flame emission spectroscopy can be used to measure concentration.