Particle Model Of Matter

Question 1

Describe how particles in a solid are arranged

Answer 1

Particles are very close together
In a regular pattern
Particles vibrate in fixed positions

Question 2

Describe how particles in a liquid are arranged

Answer 2

Particles are close together
Particles are arranged in a random pattern
Particles can move around each other

Question 3

Describe the arrangement of particles in a gas

Answer 3

Particles are very far apart
Particles are not arranged in any pattern
Particles move very rapidly

Question 4

What is density

Answer 4

The density of a material tells us the mass for a given volume

Question 5

What’s the equation for density

Answer 5

Density (kg/m3) = mass(kg) / volume(m3)

Question 6

Describe the density of a solid

Answer 6

Very high density
As particles are packed closely together solids have a lot of mass for their volume

Question 7

Describe the density of a liquid

Answer 7

High density
Particles are close together so liquids have a lot of mass for their volume

Question 8

Describe the density of a gas

Answer 8

Low density
As particles are very far apart so gases only have a small mass for their volume

Question 9

What is internal energy

Answer 9

Internal energy is the energy stored in a system by the particles
Internal energy is the total kinetic energy and potential energy of all the particles that make up a system

Question 10

Describe melting in terms of internal energy

Answer 10

Heat a solid
Causes increase in internal energy
At some point the solid can turn into a liquid

Question 11

Explain boiling in terms of internal energy

Answer 11

Heat the liquid
This increases internal energy
At some point the liquid will turn into a gas

Question 12

Explain condensation in terms of internal energy

Answer 12

Cool a gas
Reduces internal energy
At some point the gas turns back into a liquid

Question 13

Explain freezing in terms of internal energy

Answer 13

Cool a liquid down
Reduces internal energy
Liquid turns to a solid

Question 14

What is sublimation

Answer 14

When a solid turns directly to a gas

Question 15

What is specific heat capacity

Answer 15

The amount of energy required to raise the temperature of 1 kg of the substance by 1 degree Celsius

Question 16

What is the equation for specific heat capacity

Answer 16

Change in thermal energy(J) = mass(kg) x specific heat capacity(J/kg degree Celsius) x temperature change(degree Celsius)

Question 17

What is the unit of specific heat capacity

Answer 17

J/kg degree Celsius

Question 18

Describe a heating graph

Answer 18

The temperature of the solid is rising as we increase the energy of the particles
The temperature stops rising and the line becomes horizontal
At this point the solid is melting
The energy is weakening the forces of attraction between particles
During the change of state the internal energy store increases but the temperature stays the same
The temperature rises again as we increase the energy of particles
This causes boiling of the liquid as forces of attraction are weakening

Question 19

What is specific latent heat

Answer 19

The amount of energy required to change the state of one kilogram of the substance with no change in temperature

Question 20

What is the specific latent heat of fusion

Answer 20

The energy required to change 1 kg of a substance from a solid to a liquid with no change in temperature

Question 21

What is the Specific latent heat of vaporization

Answer 21

The energy required to change 1 kg of a substance from a liquid to a vapour with no change in temperature

Question 22

Equation for specific latent heat

Answer 22

Energy for a change of state (J) = mass(kg) x specific latent heat (J/kg)

Question 23

What is the unit for specific latent heat

Answer 23

J/kg

Question 24

Explain the motion of particles in a gas

Answer 24

Move in constant random motion
The temperature of the gas is related to the average kinetic energy of the molecules

Question 25

What happens if you change the temperature of a gas held at a constant volume

Answer 25

Changes the pressure exerted by the gas

Question 26

Explain how pressure increases in a gas

Answer 26

High temperatures cause particles to have higher kinetic energy
So there are more collisions per second
These are higher energy collisions

Question 27

Explain how gas pressure increases due to force

Answer 27

Particle collisions cause a force which acts at right angles to the walls of the gas container
This force acting over the area of the container causes gas pressure

Question 28

Explain the affect of increasing volume of pressure in a gas

Answer 28

Increased spacing between particles
Particles now travel much further before colliding with the walls
Reduced number of collisions per second between the particles and the walls of the container
Reducing pressure

Question 29

What is the equation linking pressure and volume

Answer 29

Pressure (Pa) x volume (m3) = constant

Question 30

What is the proportionality between pressure and volume

Answer 30

Pressure is inversely proportional to the volume

Question 31

What is work

Answer 31

The transfer of energy by a force

Question 32

Explain what happens when you do work on a gas

Answer 32

Increases internal energy of the gas
Can cause an increase in temperature of the gas