C2.1 Seperating Mixture OCR A GCSE Chemistry

Quizlet Official Flashcards.

Filtration

Separates insoluble solids from liquids.

Crystallisation

The formation of crystals by cooling a saturated solution

Simple distillation (uses)

Used to separate a liquid from a solution

Fractional distillation

separation of a liquid mixture into fractions with different boiling points using a fractionating column.

Solution

A mixture that forms when one substance dissolves another.

Solvent

A substance which is capable of dissolving other substances

Solute

A substance that is dissolved in a solution.

Insoluble

incapable of being dissolved in a given solvent

Soluble

capable of being dissolved in a given solvent

Saturated

A solution that cannot dissolve any more solute at a given temperature

Chromatography

Separates the components of a mixture based on their solubility.

Filtrate

Liquid that has passed through a filter

Residue

Insoluble solid which remains in the filter paper

Reason simple distillation works

Separates substances with different boiling points

Condenser

Gases pass through the tube, are cooled by the cold water and condense

First step of simple distillation

Heat the mixture so the solvent evaporates

Pure substance

Either a single element or a single compound

Mixture

A combination of two or more substances that are not chemically combined

Formulation

A mixture that has been designed for a specific purpose

Melting/boiling point of pure substances

A single defined temperature

Melting/boiling points of mixtures

A range of temperatures

Melting point of pure water

0 °C

Boiling point of pure water

100 °C

Examples of formulations

Paint, processed food, fuels, cleaning products, cosmetics

Test for purity

Test melting/boiling point

Test if water is pure

Test if boiling point is exactly 100 °C

Solution

A mixture that forms when one substance dissolves another

Chromatography

Separates the components of a mixture based on their solubility

Mobile phase of chromatography

Solvent, which moves up the stationary phase

Stationary phase of chromatography

The substances the mobile phase moves through, usually paper

Rf factor

A measurement of how far components of a mixture moves up a chromatogram

Chromatogram

The chromatography strip at the end of the experiment

Rf formula

distance traveled by spot ÷ distance traveled by solvent

Solvent front

The furthest point reached by the solvent

Rf of the same chemical

Is always the same in the same solvent

Pure substance on chromatogram

Will produce one spot in the same vertical column

Mixtures on a chromatogram

Will produce more than one spot in the same vertical column

A substance moves at different speeds

depending on how attracted it is to the stationary/mobile phase

Identification of chemicals using chromatography

Compare Rf to known substances in a database

Thin Layer Chromatography (TLC)

A type of chromatography that uses a thin layer of powder on a plate as the stationary phase