C2 Mixtures

Question 1

What are substances

Answer 1

They aren’t chemically joined just mixed up

Question 2

How do you separate a compound

Answer 2

Using a chemical reaction

Question 3

What are mixtures properties

Answer 3

The substance in the mixture keep their own properties

Question 4

What are the properties in a compound

Answer 4

A compound has different properties to those of its elements

Question 5

What is a pure substance

Answer 5

A substance is pure if it has no other substances mixed with it

Question 6

What is an impure substance

Answer 6

A substance is impure if it has different substance mixed with it

Question 7

How can you identify a pure substance

Answer 7

It will have a sharp melting point - it will stay at the same temperature until all the solid has melted

Question 8

Are there other mixtures

Answer 8

Most materials are mixtures some are natural:
Most rocks are mixture of compounds
Seawater is a mixture of water, sodium chloride and other salts

Question 9

What is a solvent

Answer 9

The liquid in which a gas or solid dissolves in

Question 10

What is a solute

Answer 10

The solid or gas that dissolves in a liquid

Question 11

How do you find out is something is in a solution

Answer 11

By colour
By mass - 1l of water = 1000g
Dissolve 20g of sugar
End mass- 1020g

Question 12

Explain dissolving

Answer 12

Water particles surround each solute particle. The solute particles can mix with the liquid and they are arranged randomly and move around

Question 13

Can gases dissolve

Answer 13

Yes- many gases dissolve in solvents

Question 14

What is an example of gas dissolving in a solvent

Answer 14

Carbon dioxide gas makes drinks fizzy - when you open the bottle the gas leaves the solution

Question 15

What is a saturated solution

Answer 15

A solution where no more solute can dissolve

Question 16

How do you make a saturated solution of salt (sodium chloride)

Answer 16

Adding more that 36g of salt into 100g of water

Question 17

What is solubility

Answer 17

The mass of solute that dissolves on 100g of water to make a saturated solution

Question 18

What does insoluble mean

Answer 18

The word given to some substances that cannot dissolve in water (sand, chalk)

Question 19

How can you dissolve more sugar into water

Answer 19

Heating up the water to a higher temperature

Question 20

What is filtration

Answer 20

Separating a liquid from an insoluble solid

Question 21

How does filtering work

Answer 21

You can separate same from water by pouring the mixture into filter paper - water passes through sand doesn’t

Question 22

What is filtrate

Answer 22

The liquid or solution that collects in the container after the mixture has passed through the filter paper

Question 23

What is residue

Answer 23

The solid that collects in the filter paper (sand)

Question 24

How do people get salt from seawater

Answer 24

Evaporation- the sun transfers energy to the water molecules and they leave the surface of the solution
when all the water has evaporated, solid salt remains

Question 25

What is distillation

Answer 25

A technique that uses evaporation and condensation to obtain a solvent from a solution

Question 26

What do you need to preform distillation

Answer 26

Thermometer
Bunsen burner
Condenser beaker
Mixture (salty water )

Question 27

How does distillation work with salty water

Answer 27

Water in the salt solution boils
Steam leaves the solution
Steam travels through the condenser and cold down
The steam condenses into liquid water
Liquid water drips into the beaker

Question 28

What is chromatography

Answer 28

A technique to separate mixtures of liquid that are soluble in the same solvent (pen inks)

Question 29

How is chromatography useful

Answer 29

To identify food nutrients

To figure out a forgery