States of Matter and Mixtures

Question 1

What are the 3 state of matter?

Answer 1

Solids, liquids and gases

Question 2

What are the properties of a solid?

Answer 2

• strong forces of attraction between particles
• fixed, regular, lattice arrangement
• keep a definite shape and volume
• expand when heated due to increased vibrations

Question 3

What are the properties of a liquid?

Answer 3

• particles are free to move but tend to stick together
• do not keep a definite shape
• keep a definite volume
• constantly moving in random motion
• expand slightly when heated

Question 4

What are the properties of a gas?

Answer 4

• no forces of attraction between particles
• particles only interact in collisions
• do not keep a definite shape or volume
• move constantly in random motion
• expand or increase pressure under higher temperatures

Question 5

What is a pure substance?

Answer 5

A substance completely made up of a singular element or compound

Question 6

What is a mixture?

Answer 6

A substance where more than one compound is present, or multiple different elements which are not a part of a singular compound.

Question 7

What is a method of testing purity?

Answer 7

• every pure substance has a specific melting point and boiling point
• can test purity by comparing the actual melting point to the expected melting point
• impure substances will change state over a range of temperatures

Question 8

What is distillation used for?

Answer 8

It is used to separate mixtures that contain liquids.

Question 9

What is simple distillation and how does it work?

Answer 9

Used to separate solutions
- add sample to distillation flask
- run cold water through a condenser attached to the distillation flask
- heat the distillation flask
- the part with the lower boiling point will evaporate and then condenser in the condenser
- eventually you will have to separate substances

Question 10

What are the problems with simple distillation?

Answer 10

• only used to separate things with very different boiling points

Question 11

What is fractional distillation?

Answer 11

Used to separate a mixture of liquids
- add your mixture to a flask
- attach a fractioning column filled with glass rods to the flask
- the liquids with evaporate beginning with the lowest one when the temperature reaches the correct temperature for the substance
- liquids with higher boiling points will condense before reaching the opening to the condenser
- once the first liquid stops evaporating, increase the temperature

Question 12

What is filtration?

Answer 12

Used to separate an insoluble solid from a liquid
- uses a funnel and filter paper to prevent the solid from going through whilst the liquid does

Question 13

What is crystallisation?

Answer 13

Used to separate a soluble solid from a liquid
- add the solution to an evaporating dish and gently heat
- once most of the water has evaporated or crystals begin to form, remove the dish and leave to cool
- the salt should form crystals and separate from the mixture

Question 14

What is chromatography used for?

Answer 14

It separates a mixture of soluble substances to allow them to be identified

Question 15

What is the mobile phase of chromatography?

Answer 15

Where the molecules can move, it is always a liquid or a gas. A solvent (water or ethanol) in paper chromatography.

Question 16

What is the stationary phase of chromatography?

Answer 16

Where the molecules cannot move, a solid or really thick liquid. A piece of filter paper in paper chromatography.

Question 17

How to do paper chromatography?

Answer 17

• draw a pencil line near the bottom of the paper (a baseline)
• put a spot of the mixture on the baseline
• add some of the solvent to the beaker and dip the bottom of the paper into it
• as the solvent moves up the paper, the chemicals in the mixture will dissolve in it and move too