Particle Model of Matter

Question 1

Describe the particle model of matter for solids

Answer 1

Arrangement: Regular
Distance: Close
Motion: Vibrate about fixed positions
Force: Strong

Question 2

Describe the particle model of matter for liquids.

Answer 2

Arrangement: Random
Distance: Close
Motion: Move around each other

Question 3

Describe the particle model of matter for gases.

Answer 3

Arrangement: Random
Distance: Far apart
Motion: Move quickly in all directions
Forces: Negligible

Question 4

What is density?

Answer 4

The mass of a substance per unit volume.

Question 5

What is the equation for density?

Answer 5

Question 6

Required Practical: Determining the density of liquids and ir/regular solids

Answer 6

Liquids: Use a measuring cylinder
Regular Solids: Use Vernier callipers/ruler and a balance
Irregular solids: A eureka can is filled up to the spout with water and the solid lowered in. The displaced water is collected in a measuring cylinder, a balance is used to find the mass

Question 7

What types of changes are changes that can be reversed?

Answer 7

Physical changes
E.g. Changes of state

Question 8

What are the six changes of state?

Answer 8

Question 9

What happens to the particles when a substance melts?

Answer 9

Energy is transferred to the particles by heating and the particles gain thermal energy so can move away from their fixed positions and start to move round each other as a liquid.

Question 10

What is decomposition?

Answer 10

Gas to solid

Question 11

What is sublimation?

Answer 11

Solid to gas

Question 12

Why do droplets of water form on the inside of a window on a cold day?

Answer 12

Energy is transferred from the water particles in the air to the colder glass and water changes from the gas state to the liquid state.

Question 13

What is internal energy?

Answer 13

The total kinetic energy and potential energy of all the particles that make up the system.

Question 14

What is specific latent heat?

Answer 14

The amount of energy required to change the state of one kilogram of a substance at a constant temperature.

Question 15

What is specific latent heat measured in?

Answer 15

J/kg

Question 16

What is the specific latent heat of fusion?

Answer 16

The amount of energy required to change 1 kg if a solid to a liquid

Question 17

What is the specific latent heat if vaporisation?

Answer 17

The amount of energy required to change 1 kg if a liquid to a gas.

Question 18

Describe what happens in a heating curve.

Answer 18

Question 19

As the average kinetic energy of the gas particles increases, the temperature of the gas …

Answer 19

Increases

Question 20

Why does pressure increase when temperature increases?

Answer 20

• The particles are moving faster so the force of each collision increases
• There are more particle collisions each second

Question 21

How is motion of particles in a fixed volume of gas related to its temperature and pressure?

Answer 21

The higher the temperature of the particles, the faster they move and the more frequently they collide with each other and the container walls, increasing the force in the container. This means that the pressure of the gas increases as the temperature increases.

Question 22

Why does the temperature of the material stop changing once it reaches a certain temperature?

Answer 22

The material is changing state. Energy is being used to break the intermolecular bonds rather than raise the temperature. Energy is transferred to the potential energy store of the particles rather than their kinetic energy stored.