Scientific methods

Question 1

What is simple distillation used for?

Answer 1

A solution that includes a solute, e.g water and salt. Makes a solid with a liquid.

Question 2

What is fractional distillation used for?

Answer 2

Separates liquids with different boiling points, uses a condenser tube.

Question 3

5 methods of separating mixtures

Answer 3

Distillation (simple and fractional), filtration, chromatography, crystillisation.

Question 4

Filtration method?

Answer 4

Used to remove large insoluble solids e.g rocks

Question 5

Crystallisation

Answer 5

Used by heating an evaporating basin to separate the solute and solution e.g salt and water (the solution evaporates)

Question 6

Method for chromatography [4 marks]

Answer 6

1. Spots of ink placed on the pencil line
2. Paper lowered into the solvent and some of the ink moves up
3. The paper has absorbed the solvent and dye has spread further up paper.
4. Calculate rf value by dividing the distance travelled by ink by distance travelled by solvent.

Question 7

Method of osmosis

Answer 7

1. 5 Beakers contain different concentrations of sucrose solution
2. Cut 5 potatoes, measure and weigh so they are a similar size
3. Add potatoes to beaker and leave for 2 hours
4. Take out and pat dry to remove excess water and then reweigh
5. Record results and calculate change in mass

Question 8

% change equation

Answer 8

Change / initial x 100