Particle Model of Matter

Question 1

How are particles in a solid arranged?

Answer 1

-Particles are very close together
-Particles arranged in regular patterns
-Particles vibrate but do not move from place to place

Question 2

How are particles in a liquid arranged?

Answer 2

-Particles are close together
-Particles not arranged in regular patterns
-Particles can move around each other

Question 3

How are particles in a gas arranged?

Answer 3

-Particles are very far apart
-Particles not arranged in any pattern
-Particles are moving very rapidly

Question 4

What is the density?

Answer 4

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

Question 5

Why do solids have a very high density?

Answer 5

Because the particles are packed closely together, solids have a lot of mass for their volume

Question 6

Why do liquids have a high density?

Answer 6

Because the particles are close together, liquids have a lot of mass for their volume

Question 7

Why do gases have a low density?

Answer 7

Because the particles are very far apart so gases only have a small mass for their volume

Question 8

What is the internal energy?

Answer 8

The energy stored in a system by the particles and the total kinetic energy (due to their movement) and potential energy of all the particles that make up a system (due to forces between particles and also the bonds between atoms in a molecule).

Question 9

What is the specific heat capacity?

Answer 9

The specific heat capacity of a substance is the amount of energy required to raise the temperature of 1 kg of the substance by 1∘C.

Question 10

What happens during the melting stage (forces)?

Answer 10

The energy we are putting in is weakening or breaking the forces of attraction between the particles the forces of attraction between the particles, allowing the substance to change from a solid to a liquid.

Question 11

What is the latent heat?

Answer 11

The energy needed for a substance to change state

Question 12

What is the specific latent heat?

Answer 12

The specific latent heat of a substance is the amount of energy required to change the state of one kilogram of the substance with no change in temperature.

Question 13

What is the specific latent heat of fusion?

Answer 13

The specific latent heat of fusion is the energy required to change 1 kg of a substance from a solid to a liquid with no change in temperature.

Question 14

What is the specific latent heat of vaporisation?

Answer 14

The specific latent heat of vaporisation is the energy required to change 1 kg of a substance from a liquid to a vapour with no change in temperature.

Question 15

What is the pressure of the gas due to?

Answer 15

The particles colliding with the walls of the container that the gas is held in and the gas particles are exerting a pressure.

Question 16

How can we increase the pressure?

Answer 16

If we increase the number of collisions per second or the energy of each collision by increasing the temperature.

Question 17

What happens if the particles are at low temperature?

Answer 17

Particles have lower kinetic energy and there are fewer collisions per second and these are lower energy collisions and there is a low pressure.

Question 18

What happens if the particles are at high temperature?

Answer 18

Particles have a higher kinetic energy and there are more collisions per second and these are more energy collisions and there is a high pressure.

Question 19

(Triple only) What causes the gas pressure?

Answer 19

The particle collisions cause a force which acts at right angles to the walls of the gas container and the force acting over the area of the container causes the gas pressure.

Question 20

(Triple only) What happens if we increase the volume of the container?

Answer 20

Then we reduce the pressure because we have increased the spacing between the particles and particles now travel much further before colliding with the walls of the container.
Which reduces the number of collisions per second between the particles and the walls if the container reducing the pressure.

Question 21

(Triple only) What happens when we carry out work on a gas?

Answer 21

A force is applied to the gas and we have transferred energy to the gas particles. Which means we have increased the internal energy of the gas. And the internal energy includes both kinetic energy and the potential energy of the gas particles. And we have increased the temperature of the gas as we have increased the kinetic energy.

Question 22

(Triple only) What happens when we apply work on a pump?

Answer 22

The pump gets warm when we use them to inflate a tyre as we are doing work on the gas increasing its internal energy.