Chemistry - Topic 2

States of matter, Mixtures, Separation techniques

Name the 3 states of matter

Name the 3 states of matter

Solid, liquid and gas

What is used to represent states of matter in particle diagrams?

Circles

Solid particle arrangement

Regular + Very close

Liquid particle arrangement

Irregular/random + Close

Gas particle arrangement

Irregular/random + Far apart

Movement of solid particles

Vibrate in fixed positions/around a fixed point

Movement of liquid particles

Particles slide around each other

Movement of gas particles

Move in random directions at random speeds

Describe the bonds/force of attraction between solid particles

Very strong

Describe the bonds/force of attraction between liquid particles

Weak

Describe the bonds/force of attraction between gas particles

Very weak/Negligible

Which state of matter has negligible forces between particles?

Gas

Is there space between solid particles?

No

Is there space between liquid particles?

No

Is there space between gas particles?

Yes

Are solid particles free to move?

No

Are liquid particles free to move?

Not completely free

Are gas particles free to move?

Yes

Do solid particles flow?

No

Do liquid particles flow?

Yes

Do gas particles flow?

Yes

Which state of matter has the most energy?

Gas

Which state of matter has the least energy?

Solid

Which state of matter has the highest density?

Solid

Which state of matter has the lowest density?

Gas

Why are particles in a solid in fixed positions?

Strong forces between particles hold them in place

Why the particles in a liquid move around each other?

They have strong forces to hold particles close together but are weak enough to allow particles to flow

Why do gas particles move quickly in all directions?

There are very weak forces between particles so particles are far apart and therefore can move a lot + move quickly as they have a lot of energy.

Can particles in a solid fill its container? Why?

No because the particles have strong forces of attraction and are in fixed positions so therefore cannot move to fill the container.

Can particles in a liquid fill its container? Why?

Yes because the particles have weak forces of attraction so can move around each other to fill the container.

Can particles in a gas fill its container? Why?

Yes because the particles have very forces of attraction so can move to fill the container.

Can solids be compressed? Why?

No because particles are already close together and there is no empty space between them so they cannot be pushed closer together.

Can liquids be compressed? Why?

No because particles are already close together and there is no empty space between them so they cannot be pushed closer together.

Can gases be compressed? Why?

Yes because particles are already far apart and there is lots of empty space between them so they can be pushed closer together.

Physical change

A non permanent change as no new product is formed; can be reversed via heating or cooling

Are state changes physical or chemical changes?

Physical

What causes a change of state?

Heating/cooling of the substance causing the particles to lose or gain energy

Change of state: Melting

Solid to liquid

Change of state: Freezing/Solidify

Liquid to solid

Change of state: Evaporation/Boiling

Liquid to gas

Change of state: Condensation

Gas to Liquid

Change of state: Sublimation

Solid to gas

Change of state: Deposition

Gas to solid

Change of state: Solid to liquid

Melting

Change of state: Liquid to solid

Freezing/Solidify

Change of state: Liquid to gas

Evaporating/Boiling

Change of state: Gas to liquid

Condensing

Change of state: Solid to gas

Subliming

Change of state: Gas to solid

Deposoition

What happens to solid particles as it is heated?

As a solid is heated, temperature rises. Particles absorb energy which causes the particles in a solid to vibrate more.

What happens to gas particles as it is heated?

As a liquid is heated, temperature rises. Particles in the liquid move past one another randomly.

Heating curve

A graph for a substance being heated comparing time against temperature

Describe a heating curve for water

• Temperature rises as you heat solid

• As solid melts, graph levels out

• Once fully liquid, continues rising

• Levels out during boiling

• Rises again once fully gas

Melting point

The temperature at which a solid converts into a liquid (Melt).

Boiling point

The temperature at which a liquid converts into a gas (evaporation).

Boiling point of water

100 degrees Celsius

Melting point of water

0 degrees Celsius

What is the state of a substance if the temperature is above the melting point but below the boiling point?

Liquid

What is the state of a substance if the temperature is below both the melting point and the boiling point?

Solid

What is the state of a substance if the temperature is above both the melting point and the boiling point?

Gas

On a heating curve, what shape/direction is the line when there is a state change?

Horizontal

During state changes, what is in between the particles that is getting weaker or stronger?

Bonds

When a substance is heated, what is absorbed by the particles causing the temperature to increase?

Heat/energy

Atom

Basic building block of all substances

Mixture

A substance containing 2 or more elements/atoms, not chemically combined.

Compound

A substance containing 2 or more elements/atoms, chemically combined.

Element

Substance containing only 1 type of atom.

Pure substance

Substance containing only 1 type of atom/element/compound with a fixed composition.

Internal energy

Total amount of kinetic and potential energy in a system.

Kinetic energy

Store of energy in a moving object.

Does an impure substance have specific boiling/melting point?

No

Does a mixture have specific boiling/melting point?

No; they have melt/boil over a range of temperatures.

Describe the melting and boiling points of mixtures

Melt/Boil over a range of temperatures; no fixed temperature

Does a pure substance have a fixed composition?

Yes

Does a compound have a fixed composition?

Yes

Does a mixture have a fixed composition?

No

Can pure substances be separated using physical methods?

No

Can impure substances be separated using physical methods?

Yes

Can mixture be separated using physical methods?

No

Can the composition of a pure substance be changed?

No

Can the composition of a mixture be changed?

Yes

Can a pure substance be separated into other substances?

No

Are the substances in a mixture chemically bonded?

No

Is air a mixture?

Yes

Solute

Substance that dissolves in the solvent.

Solvent

The liquid a solute dissolves in.

Solution

A mixture of solute dissolved in a solvent.

Soluble

When a substance can be dissolved by a liquid

Insoluble

When a substance cannot be dissolved by a liquid

Dissolving

A process causing solute particles to fill spaces between solvent particles.

What is typically the solvent?

Water

Does salt react or dissolve in water?

Dissolve

Name methods of separating a substance

Filtration, Chromatography, Distillation

Distillation

A separation technique to separate a liquid from a solution and get a pure liquid.

Condenser

A glass tube surrounded by ice/cool water

What is the job of the condenser?

To stop the gas escaping by turning a gas into a liquid (condensation) before it reaches the conical flask. Increases volume collected and rate of condensation

Anti bumping granules

Make the liquid boil smoother to decrease the risk of large bubbles boiling over.

What separation technique uses a condenser?

Distillation

In distillation, what heats the flask of mixture?

A Bunsen burner

In distillation, which liquid flows in and out of the condenser?

Water