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level: Analysing and identifying substances

Questions and Answers List

level questions: Analysing and identifying substances

QuestionAnswer
How can you tell the difference between a pure substance and a mixture?A pure substance has a sharp melting point but mixtures melt over a range of temperatures
What is a formulation?A mixture designed as a useful product e.g. fuels, cleaning products, paint
How can u tell if a substance is pure through a chromatogram?A pure substance has one spot but an impure substance will produce 2 or more spots.
Chromotography required practical?1)draw a pencil line across the chromatography paper, 1 - 2 cm from the bottom 2)use a pipette or capillary tube to add small spots of each ink to the line on the paper 3)place the paper into a container with a suitable solvent in the bottom 4)allow the solvent to move through the paper, but remove the chromatogram before it reaches the top 5)allow the chromatogram to dry, then measure the distance traveled by each spot and by the solvent