Separating and Analysing

Question 1

Making pure salt from rock salt 1 soluble 1 insoluble

Answer 1

Crush/mix salt with hot water. Impurities filtered with paper. Boil salt solution.

Question 2

Making pure water from sea water

Answer 2

Solution boiled, then condensed, salt remains in flask

Question 3

Fractional Distillation

Answer 3

Different boiling points, boil at lowest then condense leaving separations.

Question 4

Recrystallisation

Answer 4

Purify soluble with other soluble substances. Solid dissolved in hot water then cooled. Most solids less soluble in cold than hot so crystals form, dry.

Question 5

Separating Petrol and water

Answer 5

They won’t mix so use a separating funnel

Question 6

Chromatography

Answer 6

Ink on chroma paper in tube with solvent (water). Dyes differ in strength to paper and solubility. Pattern chromatogram. Low stick less soluble high opposite

Question 7

Chromatography equation

Answer 7

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