CP13 Determining the specific latent heat of phase change

Question 1

How? (the specific latent heat of a solid)

Answer 1

Weight the initial mass of each beaker
Crush ice and place in the funnel
submerge the heater into the funnels of ice
Switch one heater on and let the other be a control
After 5 minutes measure the mass of the water in each beaker
Find the difference in their masses and then use the formula

Question 2

What formula is used for the specific latent heat of a solid practical?

Answer 2

E = Δm x L so,
L = E/ Δm and
E =Power x time and
Power = IV finally

L = I x Vx t /Δm

Question 3

Reducing uncertainty

Answer 3

Ice must already be on the verge of melting (at 0)
Ice must be crushed so that it cools the water down quickly reducing error from surrounding heat
The uncertainty is +/ - 1 C
Add lagging to the beaker to insulate it from surrounding heat

Question 4

How? ( Specific latent heat to a liquid)

Answer 4

Set up double-walled glass vessel
Measure initial mass
Turn on the heater and start the watch
Record V and I
Switch heater off after 5 mins
find the mass of the evaporated water

Question 5

Why must the ice be on the verge of melting?

Answer 5

To reduce the uncertainty from the heating of the ice from the surroundings,