P3 - Particle Model of Matter

Question 1

What is the definition of density?

Answer 1

The mass per unit of volume of a material.

Question 2

What is the equation for density?

Answer 2

density = mass / volume

Question 3

Describe the particle arrangement in a solid.

Answer 3

Tightly packed in a regular arrangement particles can only vibrate on the spot.

Question 4

Describe the particle arrangement of a liquid.

Answer 4

Close together but with an irregular arrangement. Particles can flow over each other.

Question 5

Describe the particle arrangement of a gas.

Answer 5

Separated with no regular arrangement. Particles can move freely.

Question 6

What is always conserved when a substance changes state?

Answer 6

Mass

Question 7

How does a change of state differ from a chemical change?

Answer 7

In a change of state, a substance can return to having it’s previous properties if the change is reversed.

Question 8

What is sublimation?

Answer 8

When a solid turns into a gas without passing through the liquid state.

Question 9

What is the internal energy of a substance?

Answer 9

The energy stored by the particles.

The total kinetic energy and potential energy of the particles.

Question 10

How does heating affect the energy of a substance?

Answer 10

Heating transfers energy to the substance.

It increases the energy of the particles that make up that substance.

Question 11

What two things can heating a substance do?

Answer 11

Raise the temperature.

Change the state.

Question 12

What three factors determine the temperature change of a system?

Answer 12

Mass.
Specific Heat Capacity.
Energy transferred to the system.

Question 13

How do you calculate temperature change when a substance is heated?

Answer 13

Temperature change = mass x SHC x inputted energy

Question 14

Define Specific Heat Capacity.

Answer 14

The amount of energy needed to increase the temperature of 1kg of a substance by 1 degree.

Question 15

How will the internal energy and temperature of a substance changes when a change of state occurs?

Answer 15

Internal energy will increase or decrease depending.

Temperature of the substance will remain constant.

Question 16

Define Specific Latent Heat.

Answer 16

The amount of energy needed to change the state of 1kg of a substance with no change in temperature.

Question 17

State the equation to calculate the energy required to change state.

Answer 17

Energy to change state = mass x SLH

Question 18

What is the SLH of fusion?

Answer 18

The amount of energy require to change 1kg of a substance from solid state to liquid state without a change in temperature.

Question 19

What is the SLH of vaporisation?

Answer 19

The amount of energy require to change 1kg of a substance from liquid state to gas state (vapor) without a change in temperature.

Question 20

What factor affects the average kinetic energy of gas molecules?

Answer 20

The temperature of the substance.

Higher the temperature, higher the average kinetic energy of the gas molecules.

Question 21

Why does pressure increase as temperature increases?

Answer 21

Kinetic energy of the molecules increases.
Leading to more collisions.
More changes of momentum.
Greater force and therefore, pressure.

Question 22

Explain how an increase in the volume of a gas results in a decrease in pressure.

Answer 22

Molecules become more spread out so time between collisions increases.
Reduces rate of collisions.
Rate of change of momentum decreases so force exerted on walls decreases, leading to a decrease in pressure.

Question 23

What is the unit used for pressure?

Answer 23

Pascal (Pa)

Question 24

What increases when you do work on a gas?

Answer 24

Internal energy. Can then also lead to a temperature change.

Question 25

Why does the temperature change inside a bike pump when it is being pumped?

Answer 25

Work is done on a gas when it is compressed.
This increases the thermal energy of the gas meaning the average kinetic energy of the molecules also, increases.
Temperature increases with an increase in kinetic energy.

Question 26

Why in a heating graph does the temperature remain constant when a change of state occurs?

Answer 26

Because the energy is being used to break or weaken the forces of attraction between the particles instead of increasing temperature.

Question 27

What is pressure?

Answer 27

Total force per unit of area.