Properties of Matter

Question 1

What is specific heat capacity?

Answer 1

The number of Joules of energy needed to raise 1kg of a substance by 1°C.

Question 2

What is meant by temperature?

Answer 2

It is a measure of the mean kinetic energy of the particles

Question 3

What is meant by heat?

Answer 3

It is the energy of the substance.

Question 4

What is conservation of energy?

Answer 4

Energy cannot be created or destroyed it can only be transferred from one type to another

Question 5

What is latent heat of vaporisation?

Answer 5

The number of Joules of energy required to change 1kg of a liquid to 1kg of a gas with no temperature change.

Question 6

What is latent heat of fusion?

Answer 6

The number of Joules of energy required to change 1kg of a solid to 1kg of a liquid with no temperature change.

Question 7

Suggest a way that we say ‘energy is lost’ (not converted to the type of energy we want)?

Answer 7

• Heat lost to the surroundings due to friction
• Sound energy lost to air because of vibrations
• Energy lost as heat to the surroundings
• Heat lost in heating up a container instead of the substance in it

Question 8

What is meant by pressure?

Answer 8

The force per unit area

Question 9

Explain how snow shoes prevent you sinking into the snow.

Answer 9

Snow shoes have a large area. So the force of the person (weight) is spread over a larger area so the pressure exterted on the snow is less as P = F/A

Question 10

These two block of wood have identical mass. Explain which exerts the greatest pressure.

Answer 10

• Both blocks have the same mass, so as W=mg will exert the same force down on the surface.
• Block B is sitting so that a small area sits on the surface, so as P = F/A it will exert a larger pressure.

Question 11

Explain why being stood on by a stilletto heel is painful.

Answer 11

Stileto heels have very small areas. So the force of the person (weight) is spread over a very small area so the pressure exterted is high as P = F/A

Question 12

What causes pressure of a gas in a container?

Answer 12

Gas particles hitting the sides of a container

Question 13

Using Kinetic Theory explain what happens to the pressure if you increase the temperature of a fixed mass gas in a fixed volume container?

Answer 13

• Pressure is caused by particles hitting the sides of the container.
• The temperature is increased. The particles gain kinetic energy.
• They will move faster and so hit the sides of the container more often and with a greater velocity / force.
• So the pressure increases.

Question 14

Using Kinetic Theory explain what happens to the pressure if you decrease the volume of a fixed mass gas at a constant temperature?

Answer 14

• Pressure is caused by particles hitting the sides of the container.
• The volume is decreased. The particles have less room to move about and so hit the sides of the container more often.
• So the pressure increases.

Question 15

Using Kinetic Theory explain what happens to the volume if you increase the temperature of a fixed mass gas at a fixed pressure?

Answer 15

• Pressure is caused by particles hitting the sides of the container.
• The temperature is increased. The particles gain kinetic energy.
• They will move faster and so hit the sides of the container more often and with a greater velocity/force.
• So the pressure increases.
• This puts pressure on a rubber bung/bead of mercury etc. and it moves. It will move until the pressure inside the container = pressure outside the container.
• So the volume will increase.

Question 16

What is meant by absolute zero?

Answer 16

• When gas particles have no energy and cannot move or collide with the sides of the container.
• They have no more kinetic energy to remove.
• Temperature cannot go below this.

Question 17

What temperature does absolute zero occur at?

Answer 17

0 K or -273 °C

Question 18

How can you convert between °C (degrees Celsius) and K (Kelvin)?

Answer 18

Temperature in degrees Celsius + 273

Question 19

What is the energy change in a buzzer?

Answer 19

Electrical to sound

Question 20

Two 1kg blocks of metal are heated up. Block A and Block B. Each block is made from a different material. They are both supplied with 10000J on energy. Block B has the biggest temperature change.

What can you say about Block B compared to Block A?

Answer 20

Block B has a lower specific heat capacity

Question 21

A temperature - time graph is shown below. What is happening at point B on the graph?

Answer 21

• The material is changing state.
• From solid to liquid

Question 22

A temperature - time graph is shown below. What is happening at point D on the graph?

Answer 22

• The material is changing state
• From a liquid to a gas.

Question 23

A temperature - time graph is shown below. What is happening at point A on the graph?

Answer 23

The temperature of the solid material is rising.

Question 24

A temperature - time graph is shown below. What is happening at point C on the graph?

Answer 24

The temperature of the liquid is increasing.

Question 25

A temperature - time graph is shown below. What is happening at point E on the graph?

Answer 25

The temperature of the gas is increasing.

Question 26

The graph below shows a temperature - time graph. Points B and D show changes in state. Explain why this can be identified from the graph.

Answer 26

When a substance changes state the temperature remains constant. (Shown by horizontal line on graph)

Question 27

Describe an experiment to investigate the relationship between the the pressure and the volume of a fixed mass of gas, at a constant temperature.

Answer 27

Boyles Law:

• Pump is used to put pressure on oil which puts pressure on a fixed mass of trapped gas.
• Valve is closed.
• Volume of air column is read off the scale.
• Pressure is read off the bourdon gauge.
• Valve is opened and closed to change the pressure to get a set of readings.
• Draw graph of pressure against volume.

Question 28

Describe an experiment to investigate the relationship between the temperature and the pressure of a fixed mass of gas, with a fixed volume.

Answer 28

• Place the flask in a beaker of water.
• Heat the water.
• As the water heats up take a set of readings.
• The temperature of the water from the thermometer
• The pressure of the gas from the bourdon gauge
• Draw graph of pressure against temperature

Question 29

Describe an experiment to investigate the relationship bewteen the volume and the temperature of a fixed mass of gas at a fixed pressure.

Answer 29

• A fixed mass of gas is trapped by a bead of mercury
• Place the capilary tube, thermometer and ruler/scale into the beaker of water.
• Heat the water.
• At different temperatures - measure the temperature of the gas from the thermometer and the volume from the ruler/scale.
• The pressure is kept constant as the bead of mercury is free to move so that the pressure reamins constant.
• Plot a graph of volume against temperature.