P1a: Heating houses

Question 1

What does heat energy flow from and to

Answer 1

Flows from a warm object to a colder object

Question 2

Describe the colours on a thermogram(3+3)

Answer 2

hottest: white/yellow/red
coolest: purple/dark blue/black

Question 3

Describe temperature(2)

Answer 3

a measurement of hotness on an arbitrary scale(can go below 0)

a measure of the average kinetic energy of particles in a substance

Question 4

Describe heat(2)

Answer 4

a measure of total energy on an absolute scale (cannot go

Question 5

Describe the specific heat capacity

• what is it
• what is it measured in
• how does it differ

Answer 5

Energy needed to raise the temperature of 1kg of the substance by 1 °C

Measured in J/kg °C

Differs for different materials

Question 6

Specific heat capacity equation

Answer 6

energy transferred = mass * SHC * temperature change

Question 7

What happens during a change of state

Answer 7

energy is still being transferred but temperature stays constant

Question 8

Why does temperature not change during change of state? (1+1)

Answer 8

Melting/boiling: Energy is used to break the intermolecular bonds between particles rather than raise the average kinetic energy of the particles

Freezing/condensing: Energy is released when intermolecular bonds form between particles so average kinetic energy of the particles doesn’t decrease

Question 9

Describe the specific latent heat

• what is it
• what is it measured in
• how does it differ

Answer 9

amount of energy needed to change the state of 1 kg of a substance without changing its temperature

J/kg

differs for different materials and each of the changes of state(different for boiling(vaporisation) and melting(fusion))

Question 10

Equation for specific laten heat

Answer 10

energy = mass × specific latent heat

Question 11

Why is the specific latent heat of vaporisation higher than that of fusion?

Answer 11

energy to completely break intermolecular forces > energy to only reduce them