Separating and purifying substances.

Describe how sedimentation is carried out. (2)

Put waste water in tank (1), the impurities fall to bottom (1)

In this experiment (of chromatography), ink sample Y did not move from the start line. Explain a change to the experiment that would be needed to separate the dyes in ink sample Y. (2)

Use a different solvent (1) so that the ink will dissolve (1)

after simple distillation the pure water collects in the beaker. Explain how the apparatus will show that the liquid collected is pure water. (2)

Use a thermometer (1) the temperature is 100 C (1)

Describe how a sample of pure, dry sodium chloride crystals can be obtained from the filtrate. (3)

Heat the solution (1) leave solution to crystallise (1) dry in oven (1)

In analysis, tests are carried out on solids dissolved in water. Explain why it is important that the water used is pure. (2)

Pure water has no other ions present (1) other ions may give a false result (1)

Give a reason why the spots of the food colourings must be above the level of the solvent, when the paper is placed in the solvent. (1)

Because spots dissolve into water (1)

After this reaction, there is a mixture of the solids magnesium, titanium and magnesium chloride. Titanium does not react with dilute hydrochloric acid. Suggest a simple method to separate titanium from the mixture. (2)

Filter the mixture (1) wash the titanuim (1)