Purification of substances
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This document discusses the purification of substances through filtration, crystallization, and distillation. It explains that a pure substance contains only one type of matter and has fixed boiling and freezing points, while impurities alter these properties. The main methods of purification remove impurities from substances by separating solids from liquids through filtration, forming crystals from solutions via crystallization, or obtaining a pure liquid from a mixture based on differences in boiling points through distillation.
Purification of substances
- 2. Characteristics of pure substances A pure substances is made up of only one substances. It is not mixed with other substances and does not contain impurities. Have fixed boiling point and freezing point Example: water have freezing point 0°c and boiling point 100°c. But, if the water added with impurities, the freezing point will lower than 0°c and the boiling point will higher than 100°c.
- 3. Method of purification Purification is a process of removing impurities from a substances. There are three method of purification: – Filtration – Crystallisation – Distillation
- 4. Filtration A process of separating solid from liquid Example: separating sand from water.
- 5. Crystallisation A process of forming crystals from a liquid or gas. Example: salt from salt solution
- 6. Distillation A process to obtain a pure liquid from a solution of mixture. Used to – Obtain pure water from a salt solution. – Obtain pure water from a sugar solution. – Separate a liquid from of mixture of miscible liquids with different boiling points.