Separating soluble substances

  1. Three substances that are soluble in water are salt, acids and bases.
  2. Fractional distillation is a process that involves separating substances by taking advantage of their different boiling points.
  3. Three substances that are insoluble in water are sand, magnesium and jelly crystals.
  4. Saltpans are giant containers containing salt and water. When the water evaporates you are left with the residue (salt).
  5. The main difference between distillation and evaporation is that with evaporation the evaporated solvent escapes to the atmosphere, whereas with distillation the evaporated solvent is captured, cooled and then stored in a container.
  6. Chromatography separatesinks, food dyes and other colour mixtures using filter paper.
  7. In chromatography, the colours move at different rates through filter paper that has been dipped in a solvent like water. This separates the colours.
  8. Three examples of distillation are: oil refining, desalinizing salt water, and distilled spirits (alcohol).
  9. Three different fractions in figure 3.3.5 are petrol, heating oil and diesel fuel.
  10. A kitchen sponge absorbs water, and charcoal filters absorb gas.
  11. a. Evaporation (water evaporates leaving salt in bowl). b.Filtration (use filter to capture dirt particles). c.Chromatography (different inks will travel through filter paper at different rates). d. Absorption (charcoal filter cleans air).

Separation method / Brief description / Example
Evaporating and Crystallization / The pure crystals of the solute are left behind called the solvent. The mixture is boiled so that the solvent evaporates. This will leave behind the solute. / Salt from sea water
Distillation / Distillation uses evaporation as well but it traps the particles instead of letting them escape. The evaporated solvent is cooled and condensed back into a liquid, which is not collected. / Using a sheet of plastic to trap water evaporating from the ground or plants.
Absorption / Absorption occurs when another takes in a material. / Silica gel separates water from materials by absorbing the moisture.
Chromatography / Chromatography is a technique that can be used to separate colours in inks, food dyes and other mixtures of colours / Paper chromatography can be used to separate the colours in the ink.
  1. If you did eat a silica gel packet it would cause severe dehydration because it can absorb nearly half your weight in water.
  2. 1. Boil the seawater in a flask. 2. Attach a condenser to a tube, which is attached to the flask. 3. Wait for condensation to occur and you will have drinking water.