Energy Transfer

Question 1

When do liquids and gases expand?

Answer 1

When they are heated.

Question 2

What does the kinetic particle theory explain?

Answer 2

The properties of the different states of matter.

Question 3

When does the rate of evaporation increase?

Answer 3

If the temperature of the liquid is increased. Or if the surface area of the liquid is increased or if air is moving over the surface of the liquid.

Question 4

How does heat energy move?

Answer 4

Conduction

Question 5

What is specific heat capacity of a substance?

Answer 5

The amount of energy needed to change the temperature of 1kg of the substance by 1 degrees C.

Question 6

What is temperature?

Answer 6

A measure of how hot something is. It is measured in degrees C.

Question 7

What does it mean to emit energy?

Answer 7

Give out energy

Question 8

What is evaporation?

Answer 8

Evaporation involves a liquid changing to a gas.

Question 9

What kind of surfaces are better at absorbing light?

Answer 9

Dark, matt surfaces.

Question 10

Explain the arrangement and movement of particles in liquids.

Answer 10

They are close together and are randomly spaced. They move around each other.

Question 11

Name some properties of gases and why they are like this.

Answer 11

They flow and completely fill their container. They are like this because the particles can move quickly in all directions. They can be compressed or squashed. They are like this because the particles are far apart and have space to move into.

Question 12

If a material has a high U-value, is it a good heat insulator?

Answer 12

No. The lower the U-value is, the better the material is as a heat insulator.

Question 13

What are evaporation and condensation?

Answer 13

Changes of state

Question 14

What is heat?

Answer 14

A measure of the thermal energy contained in an object. It is measured in Joules.

Question 15

Explain the arrangement and movement of particles in gas.

Answer 15

They are far apart and randomly spread. They move quickly in any direction.

Question 16

Name some of the properties of solids and why they are like this.

Answer 16

They have a fixed shape and cannot flow. They are like this because the particles cannot move from place to place. They cannot be compressed or squashed. They are like this because the particles are squashed and have no space to move into.

Question 17

Explain the arrangement and movement of particles in solids.

Answer 17

They are close together and have a regular pattern. They vibrate about in a fixed position.

Question 18

What are U-values?

Answer 18

U-values measure the effectiveness of a material as an insulator in buildings.

Question 19

What is another name for thermal radiation?

Answer 19

Infrared radiation.

Question 20

How can heat be transferred from place to place?

Answer 20

Conduction, convection and radiation.

Question 21

When does the rate of condensation increase?

Answer 21

The rate of condensation increases if the temperature of the gas is decreased.

Question 22

What is payback time of an energy-saving solution?

Answer 22

A measure of how cost-effective it is. The payback time will be shortest if the cost of installation is low compared to the savings made each year.

Question 23

What is the equation to calculate payback time?

Answer 23

payback time (years)= cost of installation (£) divided by savings per year in fuel costs (£)

Question 24

What is condensation?

Answer 24

Condensation involves a gas changing to a liquid.

Question 25

When does convection occur?

Answer 25

Convection occurs when particles with a lot of heat energy in a liquid or gas move and take the place of particles with less heat energy. Heat energy is transferred from hot places to cooler places by convection.

Question 26

Name some of the properties of liquids and why they are like this.

Answer 26

They flow and take the shape of their container. They are like this because the particles move around each other. They cannot be compressed or squashed. They are like this because the particles are close together and have no space to move into.

Question 27

What is the difference between non-metals, gases and metals?

Answer 27

Metals are good conductors of heat but non-metals and gases are usually poor conductors of heat.

Question 28

How is radiation different to conduction and convection?

Answer 28

It can pass through the vacuum of space.

Question 29

Why does water have such a high specific heat capacity?

Answer 29

Water has a particularly high specific heat capacity. This makes water useful for storing heat energy, and for transporting it around the home using central heating pipes.

Question 30

What are the nine types of energy?

Answer 30

Electrical - Whenever a current flows Light - From the sun, light bulbs etc. Sound - From loudspeakers or anything that emits sound Kinetic or movement - Anything that moves Nuclear - Released only from nuclear reactions Thermal or heat - Flows from hot objects to colder ones Gravitational potential energy - Possessed by anything which can fall Elastic potential energy - Stretched springs, elastic, rubber bands etc. Chemical - Possessed by foods, fuels, batteries etc.

Question 31

List three examples of stored energy. Why are they forms of stored energy?

Answer 31

Gravitational potential energy Elastic potential energy Chemical energy They are forms of stored energy because the energy is not obviously doing anything, it's kind of waiting to happen i.e. waiting to be turned into one of the other forms.

Question 32

There are plenty of different types of energy, but they all obey a particular principle. What is it?

Answer 32

Energy can be transferred usefully from one form to another, stored or dissipated but it can never be created or destroyed.

Question 33

What does dissipated mean?

Answer 33

Dissipated is a fancy way of saying the energy is spread out and lost.

Question 34

When is the only time that energy is useful?

Answer 34

Energy is only useful when it can be converted from one form to another.

Question 35

What does a sankey diagram do?

Answer 35

Sankey diagrams summarise all the energy transfers taking place in a process. The thicker the line or arrow, the greater the amount of energy involved.

Question 36

Why do liquids and gases expand when heated?

Answer 36

The particles in liquids and gases move faster when they are hot as to when they are cold.