P6

Question 1

internal energy of a substance

Answer 1

• the energy stored by the particles of a substance

- sum of kinetic and potential energy

Question 2

what is specific latent heat of fusion(or of vaporisation)?

Answer 2

-the energy needed to melt or boil 1kg of a substance without changing its temperature

Question 3

energy and states

Answer 3

• energy is needed to melt a solid or to boil a liquid

- flat section of a temp-time graph gives the melting point or boiling point of a substance

Question 4

what is latent heat?

Answer 4

-the energy needed for a substance to change its state without changing it temperature.

Question 5

Density equation

Answer 5

density= mass/volume (in kg/m3)
Or
mass=density x volume
Or
volume=mass/density

Question 6

conservation of mass

Answer 6

when a substance changes state, its mass stays the same because the number if particles stays the same

Question 7

gas pressure and volume

Answer 7

• if its pressure is increased its volume decreases

- reducing the volume of a gas increases the number of molecular impacts per second on the surface

Question 8

latent heat equation

Answer 8

Lf= E/M
Or
E=M x Lf
Lf=specific latent heat of fusion(J/Kg)
Energy
E=energy(joules,j)
M=mass(kilograms,kg

Question 9

gas pressure and temp

Answer 9

-if the temp of a gas in a sealed container increases, the pressure of the gas increases because the molecules move faster so hit the surface with more force.

Question 10

what is brownian motion?

Answer 10

-the random motion of particles suspended in a fluid resulting from their collision with the fast-moving atoms