Topic 3 - Particle Model Of Matter

Question 1

Density equation

Answer 1

Density(kg/m^3)= mass(kg) : volume(m^3)

Question 2

What are the 3 states of matter?

Answer 2

Solid, Liquid and Gas

Question 3

For each state of matter, describe the arrangement and movement of the particles.

Answer 3

Solid- Fixed, regular arrangement with particles only vibrating in their fixed positions.
Liquid- Particles are close together, but can move past eachother, and form irregular arrangements. The particles move in random directions at low speeds.
Gas- Particles are loose and in no particular arrangement with almost no forces of attraction between eachother. They are free to move, and travel in random directions at high speeds.

Question 4

Practical:
Describe how you could find the volume of an irregular solid object.

Answer 4

1. Use a balance to measure mass
2. Submerge the object in a eureka can filled with water. The water displaced by the object is transferred to a measuring cylinder.
3. Record the volume of water in the measuring cylinder. This is the volume of the object.
4. Use the formula m=PV to find out the density.

Question 5

Practical:
Briefly describe an experiment to find the density of a liquid.

Answer 5

1. Place a measuring cylinder on a balance and zero the balance.
2. Pour 10ml of the liquid into the measuring cylinder and record the liquid’s mass and volume.
3. Pour another 10ml into the measuring cylinder and record the total volume and mass.
4. Repeat until the measuring cylinder is full
5. For each measurement, use the formula m=PV to find out the density.
6. Finally take an average of the densities to get the accurate density for the liquid.

Question 6

What is internal energy?

Answer 6

The total energy that the particles of a system have in their kinetic and potential energy stores.

Question 7

What happens to the particles in a substance when that substance is heated?

Answer 7

They gain energy in their kinetic energy stores and move faster, which increases the internal energy.

Question 8

Name the 5 changes of state

Answer 8

Solid -> Liquid (melting)
Liquid -> Solid (freezing)
Liquid -> Gas (boiling/evaporating)
Gas -> Liquid (condensing)
Solid -> Gas (sublimating)

Question 9

Is a change of state a physical or a chemical change?

Answer 9

Physical change.

Question 10

True or False? Mass stays the same when a substance changes state.

Answer 10

True

Question 11

Explain the cause of the flat sections on a graph of temperature against time for a substance being heated.

Answer 11

Energy is being transferred by heating/cooling but not being used to change the temperature.

Question 12

Define specific latent heat.

Answer 12

The amount of energy needed to change 1 kg of a substance from one state to another without changing it’s temperature.

Question 13

What is meant by the term ‘specific heat of fusion’?

Answer 13

The specific latent heat for changing between a solid and a liquid(melting/freezing)

Question 14

What is meant by the term ‘specific heat of vaporisation’?

Answer 14

The specific latent heat between a liquid and gas (evaporating/condensing).

Question 15

What is meant by the term ‘specific heat of vaporisation’?

Answer 15

The specific latent heat between a liquid and gas (evaporating/condensing).

Question 16

Explain how a gas in a sealed container exerts a pressure on the walls of the container.

Answer 16

As gas particles move about at high speeds, they bang into eachother and whatever else happens to get in the way. When they collide into the walls of the container they exert a force, and so a pressure, on it.

Question 17

A sealed container of gas is kept at a constant temperature. The volume of the container is increased. What happens to the pressure of the gas? Explain why.

Answer 17

It decreases, because the particles get more spread out and hit the walls of the container less often.

Question 18

For a fixed mass of gas at a constant temperature, what is the relationship between pressure and volume?

Answer 18

pV = constant

Question 19

True or False? For a gas at constant temperature, increasing the volume of the gas will also increase its pressure.

Answer 19

False

Question 20

A balloon containing a fixed mass of helium gas is moved from an area of high atmospheric pressure to one of low atmospheric pressure. What will happen to the volume of helium in the balloon?

Answer 20

It increases.

Question 21

Explain why blowing up a football with a pump causes the ball to warm up.

Answer 21

The gas applies pressure to the plunger of the pump and so exerts a force on it. Work has been done against this force to push down the plunger. This transfers energy to the kinetic energy stores of the gas particles, increasing the temperature, so the football gets warmer.