Topic 14- Matter

Question 1

What is the kinetic (particle) theory?

Answer 1

All matter is made up of tiny particles that are constantly moving

Question 2

Describe the properties of a sold?

Answer 2

• Strong force of attraction (between particles) Hold them close together (in fixed position) - forming a ‘regular lattice structure’
• Bc particles r fixed, they hold a definite shape & vol
• Can vibrate

Question 3

What happens when we heat up a solid?

Answer 3

-Particles will gain more energy & start to vibrate even more (weakens the forces between them) —At their ‘melting point’ particles break free of the bonds
Turning solid to liquid

Question 4

Describe the properties of a liquid?

Answer 4

-Free to move around & arranged randomly
-Weak forces of attraction (between particles) =
particles stick together & fairly compact =
have a ‘definite vol’
-Overall shape can change (flow to fit a container)

Question 5

What happens when you heat up a liquid?

Answer 5

• Gains more energy (particles moves faster) - weakens forces holding particles together
• At their ‘boiling point’ will have enough energy to break bonds altogether - so liquid boils & evaporates into gas

Question 6

Describe the properties of a gas?

Answer 6

• Forces of attraction is very weak (free to move around)
• Do not keep definite shape or vol instead will fill a container
• Constantly moving with random motion (travel in any direction)

Question 7

What happens when we heat up a gas?

Answer 7

-Particle get more energy (move faster)
either they’ll - expand if container is expandable (i.e. ballon)
- if container is fixed pressure will increase

Question 8

What happens when you cool a gas down?

Answer 8

-Wont have enough energy to over forces of attraction =

Bonds will form between particles - condensing gas into a liquid

Question 9

What happen if you cool down a liquid?

Answer 9

-Wont have enough energy to over forces of attraction =

Even more bonds will form - fixing particles into place (turns liquid to solid)

Question 10

When substance changes shape what is conserved?

Answer 10

mass

Question 11

Describe & explain if changes of state are physical or chemical?

Answer 11

• Changes of state r not same as chemical changes bc states r reversible
• If state was chemical then it would be irreversible

Question 12

Define closed system

Answer 12

A physical system that doesn’t exchange any matter with its surroundings

Question 13

What happens if you’re working in a closed system? (particles)

Answer 13

-Changes in state won't change the mass
(still the same n.o of particles)
BUT
Density will change: 
solids = highest density 
liquids = lower density
gas = lowest density