level: Analysing and identifying substances
Questions and Answers List
level questions: Analysing and identifying substances
| Question | Answer |
|---|---|
| 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 |