7E - Separation techniques

Question 1

What is a suspension?

Answer 1

A type of mixture where the solids settle out over time.

Question 2

What is a colloid?

Answer 2

A type of mixture where the solid pieces are smaller so they don’t settle out. The mixture looks cloudy or opaque.

Question 3

What is a solution?

Answer 3

A type of mixture where the solids break up intosuch small pieces that the mixture is transparent.

Question 4

What is a solute?

Answer 4

A solid in a solution.

Question 5

What is a solvent?

Answer 5

The liquid in which the solute(the solid) dissolves.

Question 6

Can gases dissolve?

Answer 6

Yes. Some can dissolve in water like oxygen and carbon dioxide.

Question 7

When an insoluble solid is added to water, what type of mixture is formed?

Answer 7

A suspension or a colloid.

Question 8

Total mass of solution =

Answer 8

mass of solvent + mass of solute

Question 9

Can other liquids apart from water be used as solvents?

Answer 9

Yes. For example, alcohol.

Question 10

A solute can’t dissolve in water. Does this mean it can’t dissolve in other sovents?

Answer 10

Not necessarily.

Question 11

What does it mean if a solution is saturated with a solute?

Answer 11

No more solute can dissolve with the same temperature and amount of solvent.

(if you want more to dissolve, you can increase the temperature or the amount of solvent).

Question 12

What is the solubility of a substance?

Answer 12

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

Question 13

What separation method is being shown?

Answer 13

Filtration.

Question 14

What can filtration separate?

Answer 14

Solids from a suspension (large pieces that haven’t dissolved).

i.e. sand from a mixture of sand and water.

Question 15

What separation method is being shown?

Answer 15

Evaporation

Question 16

What mixtures can evaporation separate?

Answer 16

Solids from a solution or colloid.

(i.e. a salt from a salt solution)

Question 17

What separation method is being shown?

Answer 17

Distillation

Question 18

What mixtures can distillation separate?

Answer 18

A liquid from any type of mixture.

(i.e. Pure water from a salt solution)

Question 19

What separation method is being shown?

Answer 19

Chromatography

Question 20

What mixtures can chromatography separate?

Answer 20

individual solutes from a mixture of solutes.

(i.e. colours found in ink).

Question 21

How can we interpret a chromatogram?

Answer 21

Each substance travels a unique distance so it can be used to identify subtances in a mixture.

Question 22

What is evaporation?

Answer 22

When a liquid turns into a gas at its surface.

Happens at any temperature (gets faster as temperature increases).

Question 23

What is boiling?

Answer 23

When all the liquid is trying to turn into a gas at the same time.

Happens at boiling temperature. (100ºC for water)

Gas is formed from the liquid below so bubbles rise.

Question 24

What are the differences between evaporation and boiling?

Answer 24

In evaporation, the only the liquid at the surface turns into a gas while in boiling the whole liquid turns into a gas.

Evaporation happens at any temperature while boiling only at boiling point.

Question 25

Describe the flame

Answer 25

Quiet yellow flame

Question 26

Describe the flame

Answer 26

Medium blue flame

Question 27

Describe the flame

Answer 27

Noisy blue flame

Question 28

For what is this flame used?

Answer 28

Safety flame: used when not heating.

Question 29

For what is this flame used?

Answer 29

Used for gentle heating.

Question 30

For what is this flame used?

Answer 30

Used for rapid heating.