7E — Mixtures and Separation

Question 1

What are the different types of mixtures?

Answer 1

The different types of mixtures are:
● suspension: the solids settle out of the mixture over time.
● colloid: the solid pieces are smaller so they don’t settle out, and the mixture looks cloudy or opaque.
● solution: the solids break up into such small pieces that they are not visible, and the mixture is transparent.

Question 2

1) What is a solution?

2) What is a solution made up of?

Answer 2

1) A solution is a solid dissolved in water. These solids are soluble.
2) A solution is made from a solute (usually a solid) and a solvent (liquid).

Question 3

1) What are substances that do not dissolve in a solvent called?
2) What are these substances called when they are mixed with water?

Answer 3

1) Substances that do not dissolve in a solvent are insoluble.
2) When an insoluble substance is mixed with water, the mixture formed may be a suspension or a colloid.

Question 4

What does solubility mean?

Answer 4

The solubility of a solute is the amount that will dissolve in a fixed amount of solvent at a particular temperature.

Question 5

1) What is filtration used to separate?

2) What is evaporation used to separate?

Answer 5

1) Filtration is used to filter solids from a suspension (i.e. large pieces of solids that have not dissolved in a liquid). Eg. sand from a mixture of sand and water.
2) Evaporation is used to separate solid substances from a solution or colloid. Eg. salt from a salt solution.

Question 6

1) What is distillation used to separate?

2) What is chromatography is used to separate?

Answer 6

1) Distillation (evaporation followed by condensation) is used to separate liquid from a mixture. Eg. pure water from a salt solution.
2) Chromatography is used to separate individual solutes from a mixture of solutes in a solvent. Eg. colours found in ink.

Question 7

1) What is a solvent?

2) What is a solute?

Answer 7

1) A solute is usually a solid.

2) A solvent is a liquid.