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

Explain the process involved when a bathroom mirror mists up.

Answer 9

Hot water evaporates to form water vapor.
Water vapor lands on cooler mirror.
Vapor condenses and returns to a liquid state on the surface of the mirror.

Question 10

What is the internal energy of a substance?

Answer 10

The energy stored by the particles.
The total kinetic energy and potential energy of the particles.

Question 11

How does heating affect the energy of a substance?

Answer 11

Heating transfers energy to the substance.
It increases the energy of the particles that make up that substance.

Question 12

What two things can heating a substance do?

Answer 12

Raise the temperature.
Change the state.

Question 13

What three factors determine the temperature change of a system?

Answer 13

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

Question 14

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

Answer 14

Temperature change = mass x SHC x inputted energy

Question 15

Define Specific Heat Capacity.

Answer 15

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

Question 16

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

Answer 16

Internal energy will increase or decrease depending.
Temperature of the substance will remain constant.

Question 17

Define Specific Latent Heat.

Answer 17

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

Question 18

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

Answer 18

Energy to change state = mass x SLH

Question 19

What is the SLH of fusion?

Answer 19

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

Question 20

What is the SLH of vaporisation?

Answer 20

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

Question 21

What factor affects the average kinetic energy of gas molecules?

Answer 21

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

Question 22

Why does pressure increase as temperature increases?

Answer 22

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

Question 23

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

Answer 23

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 24

What is the unit used for pressure?

Answer 24

Pascal (Pa)

Question 25

What increases when you do work on a gas?

Answer 25

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

Question 26

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

Answer 26

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 27

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

Answer 27

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