Particle Model of Matter

Question 1

What can be used to explain the different states of matter and their properties?

Answer 1

Kinetic theory

Question 2

In solids, what are the forces like & what do they do?

Answer 2

Strong forces of attraction hold particles close together in fixed, regular arrangement

Question 3

In solids, how much energy does particles have and what does this mean?

Answer 3

Particles don’t have much energy = only vibrate about their fixed positions

Question 4

In solids, what is the density like and why?

Answer 4

Highest density = particles are closest together

Question 5

What are the forces like in liquids?

Answer 5

Weaker forces of attraction between particles

Question 6

What’s the arrangement like in liquids?

Answer 6

Particles are close together but can move past each other = form irregular arrangements

Question 7

In liquids, how much energy does particles have and what does this mean?

Answer 7

Have more energy than solids = particles move in random directions at low speeds

Question 8

In liquids, what is the density like?

Answer 8

Less dense than solids

Question 9

What are the forces like in gas?

Answer 9

Almost no forces of attraction between particles

Question 10

In gases, how much energy does particles have and what does this mean?

Answer 10

Have more energy (than in liquids + solids) = particles free to move & travel in random directions at high speeds

Question 11

In gases, what is the density like?

Answer 11

Low - less dense than liquids

Question 12

Draw the arrangement of particles in a solid

Answer 12

Question 13

Draw the arrangement of particles in a liquid

Answer 13

Question 14

Draw the arrangement of particles in a gas

Answer 14

Question 15

A Change of State _______ ____

Answer 15

Conserves Mass

Question 16

Internal energy is stored by the _____ that makes up a ____

Answer 16

the Particles that makes up a System

Question 17

When does a change in state occur?

Answer 17

If substance heated enough = particles will have enough energy in their kinetic energy stores to break bonds holding them together

Question 18

What is latent heat?

Answer 18

Energy needed to change state of substance

Question 19

When substance is melting or boiling, what are you doing essentially?

Answer 19

Putting in energy = increasing internal energy

Question 20

When a substance is melting or boiling, what is the internal energy used for?

Answer 20

Used for breaking intermolecular bonds rather than raising temperature

Question 21

What do flat spots on heating graph represent?

Answer 21

Where energy is being transferred by heating but not being used to change temperature

Question 22

When a substance is condensing or freezing, how is energy released?

Answer 22

Bonds are forming between particles = which releases energy

Question 23

When a substance is condensing or freezing (bonds are forming between particles), what does this mean for internal energy and temperature?

Answer 23

Means internal energy decreases BUT temperature doesn’t go down until all substance has turned to liquid or solid

Question 24

Draw a heating graph

Answer 24

Question 25

Draw a cooling graph

Answer 25

Question 26

What is specific latent heat?

Answer 26

Amount of energy needed to change 1 kg of a substance from one state to another without changing its temperature

Question 27

For cooling, SLH is energy _____ by a change in state

Answer 27

released

Question 28

What is latent heat of fusion?

Answer 28

Amount of energy needed to change the state of 1 kilogram of a substance from a solid to a liquid with no change in temperature

Question 29

What is latent heat of vaporisation?

Answer 29

Amount of energy needed to change the state of 1 kilogram of a substance from a liquid to a vapour with no change in temperature

Question 30

What does impurities affect?

Answer 30

Melting point of solid & boiling point of liquid

Question 31

What is specific heat capacity?

Answer 31

Amount of energy needed to raise the temperature of 1kg of a substance by 1°C

Question 32

Greater mass of object = …

Answer 32

more slowly temperature increases when heated

Question 33

Energy may be transferred by _____ and _____

Answer 33

evaporation and condensation

Question 34

What does the rate at which an object transfers energy by heating depends on? (name 3 things)

Answer 34

• Material of object
• Its surface area and volume
• Nature of the surface with which the object is in contact

Question 35

Bigger the temperature difference between an object and its surroundings = …

Answer 35

faster the rate at which energy is transferred by heating

Question 36

Most substances _____ when heated

Answer 36

expand

Question 37

When does evaporation happen?

Answer 37

When a liquid turns into a gas below its boiling point

Question 39

What is the cooling of a liquid by evaporation caused by?

Answer 39

Faster-moving particles escaping from the liquid

Question 40

How can evaporation be increased? (name 3 ways)

Answer 40

• Increasing SA of liquid
• Increasing temp. of liquid
• Creating a draught of air across liquid’s surface

Question 41

When does condensation happen?

Answer 41

When a gas turns into a liquid

Question 42

How can condensation on a surface be increased? (name 2 ways)

Answer 42

• Increasing area of surface
• Reducing temperature of the surface

Question 43

What do cooling fins on motorcycle engine do?

Answer 43

Find increase SA of engine in contact with air = engine transfers energy to surroundings faster

Question 44

Gases expand on heating much ____ than solids and liquids

Answer 44

more

Question 45

Expansion of substances on heating can be a ____ or _____

Answer 45

hazard or useful

Question 46

How do bimetallic strips work?

Answer 46

1. Consists of 2 different metals (e.g. brass and steel) bonded together
2. When temp. of strip increases = one metal expands more than other (e.g. brass more than steel) = so strip bends
3. Used to switch on or off an electrical device

Question 47

Where are expansion gaps needed?

Answer 47

In buildings, bridges, railways tracks

Question 48

Why are expansion gaps needed in bridges?

Answer 48

Temperature changes = expansion of bridge = bridge would buckle