P6: Molecules And Matter

Question 1

What is Density?

Answer 1

The mass per unit of volume (of an object)

Question 2

What is the equation for density?

Answer 2

Density = Mass/Volume

Question 3

How do you find the density of a regular object?

Answer 3

You find the mass and find the volume

You then subsitute these measurements into the equation: Density = Mass/volume too find the density

Question 4

How do you find the density of an irregular object?

Answer 4

1) First you must find the mass of your object
2) Secondly you must fill a eureka can up to the sprout, allowing excess water to drain out.
3) Gently place your irregular object into the eureka can, collecting any water which falls out through the sprout in a beaker.
4) Transport the displaced water from the beaker too a meassuring cylinder to measure the volume of the water.
5) Use your now collected volume and mass to calculate the density using the equation: Density = Mass/volume.

Question 5

Describe the properties of a solid

Answer 5

• Particles are not free to flow
• Particles in a fixed shape
• Fixed volume
• More dense than a liquid or gas

Question 6

Describe the properties of a liquid

Answer 6

• Particles are free to flow
• Particles are not in a fixed shape
• Fixed volume
• More dense than a gas

Question 7

Describe the properties of a gas

Answer 7

• Particles are free to flow
• Particles are not in a fixed shape
• Not a fixed volume
• Less dense than a solid or liquid

Question 8

What are the changes of state between gases and liquids called?

Answer 8

Liquid —> Gas = Evaporation
Gas —> Liquid = Condensation

Question 9

What are the changes of state between gases and solids called?

Answer 9

Solid —> Gas = Sublimation
Gas —> Solid = Deposition

Question 10

What are the changes of state between liquids and solids called?

Answer 10

Solid —> Liquid = Melting
Liquid —> Solid = Freezing

Question 11

What is the conservation of mass?

Answer 11

Substances do not gain/lose any mass after a change of state

Question 12

What is the melting point of a substance?

Answer 12

The temprature at which a substance changes from a solid too a liquid

Question 13

What is the boiling point of a substance?

Answer 13

The temprature at which a substance changes from a liquid to a gas

Question 14

Why do substances not gain any temprature when changing states?

Answer 14

As all of the energy is being put into breaking the bonds between the particles too change state

Question 15

What is internal energy?

Answer 15

The particles in a substance have energy, this is called ‘internal energy’ - this relates to the particles motion and position

Question 16

What is the equation for internal energy?

Answer 16

Internal energy = Kinetic energy + potential energy

Question 17

What is latent heat?

Answer 17

The energy transferred when a substance changes state

Question 18

What is specific latent heat of fusion?

Answer 18

The energy supplied to change 1kg of a substance from solid to liquid state

Question 19

What is the specific latent heat of vaporisation?

Answer 19

The heat needed to turn 1kg of liquid into gas at its boiling point

Question 20

What is the equation for specific latent heat?

Answer 20

Specific latent heat = Energy (J) / Mass (kg)

Question 21

What is gas pressure caused by?

Answer 21

Gas pressure is caused by the random collisions of particles against any surface that the gas comes into contact with

Question 22

What is the brownian motion?

Answer 22

The random (unpredictable) movement of particles in fluids as they constantly collide with other molecules

Question 23

If a sealed container is heated, explain what happens to the pressure exerted on the container?

Answer 23

When the container is heated, the gas particles inside begin to vibrate faster due to an increase in kinetic energy. This means the particles collide with the surface of the container more frequently and with more force. This results in more pressure being exerted, as the equation for pressure is force/area