yr 9 chemistry revision-separation techniques

yr 9 chemistry revision - separation techniques

Filtration

• a process used to separate solids from liquids or gases using a filter medium.

• it allows the fluid to pass through but not the solid. 

• separate an insoluble solid from a liquid

Multiple Choice

The equipment required for filtration is

• filter paper, beaker, test tube

• filter paper, funnel, beaker

• filter paper, funnel, test tube

• funnel, beaker, test tube

Crystallisation

• put the solution in an evaporating basin

• warm the solution by placing the evaporating basin over a boiling water bath

• stop heating before all the solvent has evaporated

• After the remaining solution has cooled down, filter it.

• Dry the crystals using a warm oven or in air.

Multiple Choice

The steps for producing crystals are

• warm, filter, dry, cool

• warm, dry, filter, cool

• warm, cool, filter, dry

• warm, dry, cool, filter

simple distillation

• separating the solvent from a solution.

• boiling points of solute and solvent are different

• solution is heated, solvent evaporates

• the solvent is condensed and cooled

• the salt does not evaporate

Multiple Choice

simple distillation is based on the fact that

• solvent and solution have different boiling points

• solvent and solute have same boiling points

• solvent and solute have different boiling points

• solvent and solution have different boiling points

Multiple Choice

In simple distillation

• solvent has a greater boiling point than solution

• solvent has a smaller boiling point than solution

• solute has a greater boiling point than solution

• solute has a greater boiling point than solvent

Fractional distillation

• a method for separating a liquid from a mixture of two or more liquids. 

• the liquids in the mixture have different boiling points

• When the mixture is heated, one liquid evaporates before the other

Multiple Select

Fractional distillation is a method for separating

• a liquid from a mixture of solutions

• a liquid from a mixture of solutes

• a liquid from a mixture of solvents

• a liquid from a mixture of liquids

Multiple Choice

In fractional distillation the liquids

• have same boiling points

• have same melting points

• have different melting points

• have different boiling points

Chromatography

• method for separating dissolved substances from one another.

• used to separate  inks, food colourings and plant dyes

• some of the coloured substances dissolve better than others

• they travel further up the paper.

Retention factor

• how much the compound has moved compared to how much the solvent has moved

• Rf = distance moved by compound ÷ distance moved by the solvent