P6: Molecules and matter

Question 1

density

Answer 1

density = mass/volume

Question 2

types of latent heat

Answer 2

The energy transferred when a substance changes state is called the latent heat.
Specific latent heat – the energy required to change 1 kg of a substance with no change in temperature.
Specific latent heat of fusion – the energy required to melt 1 kg of a substance with no change in temperature.
Specific latent heat of vaporisation – the energy required to evaporate 1kg of a substance with no change in temperature

Question 3

latent heat equation

Answer 3

thermal energy for a change in state = mass X specific latent heat

Question 4

gas

Answer 4

particles are spread out have almost no force or attraction. particles move randomly at high speed.low denstiy no fixed volume or shape can be compressed and can flow spread out to fill all available space

Question 5

liquid

Answer 5

particles are in contact with each other forces of attraction between particles weaker then solids. particles are free to move randomly around each other. usually lower density then solids fixed volum shape is not fixed so they can flow

Question 6

solid

Answer 6

particls held next to each other in fixed positions by strong forces of attraction. particles vibrate about fixed positions. high density fixed volume fixed shape

Question 7

pressure

Answer 7

If the volume of a fixed mass of gas at a constant temperature is decreased, the pressure increases because the distance the particles travel between each impact with a container wall is smaller
the number of impacts per second increases, so the total force of impacts increases. Similarly, if the volume is increased, the pressure decreases.
This is because the distance the particles travel between each impact with a wall of the container is greater the number of impacts per second decreases, so the total force of the impacts decreases.

Question 8

pressure equation

Answer 8

pressure x volume = constant