C1 - Atomic
Structure
, Mixtures and separation
• A mixture consists of two or more elements or compounds, mixed but not chemically combined
together. The chemical properties of the substances in the mixture are unchanged.
• Mixtures can be separated using physical processes such as filtration, crystallisation, simple
distillation, fractional distillation and chromatography.
• When the components of a mixture are separated, a chemical reaction doesn’t take place and no
new substances are made.
• Compounds can only be separated by chemical reactions.
Crystallisation
• is used to obtain pure salt (NaCl) from salt solution following filtration, you need to separate the
sodium chloride (filtrate) from the water.
• you can do this by evaporating the water from the sodium chloride solution by heating it in an
evaporation dish on a water bath.
• when the solution is at the point of crystallisation, heating is stopped and the rest of the water is left
to evaporate at room temperature.
• flat bottomed crystallisation dishes or petri dishes can be used for the final step, to give a large
surface area for the water to evaporate from.
Structure
, Mixtures and separation
• A mixture consists of two or more elements or compounds, mixed but not chemically combined
together. The chemical properties of the substances in the mixture are unchanged.
• Mixtures can be separated using physical processes such as filtration, crystallisation, simple
distillation, fractional distillation and chromatography.
• When the components of a mixture are separated, a chemical reaction doesn’t take place and no
new substances are made.
• Compounds can only be separated by chemical reactions.
Crystallisation
• is used to obtain pure salt (NaCl) from salt solution following filtration, you need to separate the
sodium chloride (filtrate) from the water.
• you can do this by evaporating the water from the sodium chloride solution by heating it in an
evaporation dish on a water bath.
• when the solution is at the point of crystallisation, heating is stopped and the rest of the water is left
to evaporate at room temperature.
• flat bottomed crystallisation dishes or petri dishes can be used for the final step, to give a large
surface area for the water to evaporate from.
