Lesson 2 Mixtures and Separation Flashcards
(17 cards)
What is a mixture?
Two or more elements or compounds not chemically combined together. The chemical properties of each substance in the mixture are unchanged.
What is the difference between a mixture and a compound?
A mixture consists of substances that are not chemically combined, while a compound consists of substances that are chemically combined.
What physical processes can separate mixtures?
Filtration, crystallisation, simple distillation, fractional distillation, chromatography.
What is filtration used for?
To separate an insoluble solid from a liquid.
What does crystallisation involve?
Evaporating a solution to a smaller volume and leaving it to cool to form crystals.
What is simple distillation used for?
To separate a solvent from a solution.
How does simple distillation work?
The dissolved solute has a higher boiling point than the solvent, allowing the solvent vapor to be collected and condensed.
What is fractional distillation used for?
To separate different liquids from a mixture of liquids.
How do vapours behave in fractional distillation?
They rise through a column that is hot at the bottom and cooler at the top, condensing when they reach a cooler part of the column.
What is paper chromatography used to separate?
Mixtures of soluble substances.
Fill in the blank: A mixture consists of two or more elements or compounds not __________ together.
chemically combined
True or False: In a mixture, the chemical properties of each substance are changed.
False
What separation technique would you use to separate pure water from sea water?
Simple distillation.
What is an example of filtration?
Separating sand from water.
What is an example of crystallisation?
Separating salt from water.
What is an example of fractional distillation?
Separating different fractions of crude oil.
What is an example of paper chromatography?
Separating food colourings.
