measurement of the specific latent heat of fusion of ice Flashcards
what measurements did the student take before adding the ice to the water?
the student measured the mass of the empty calorimeter, the calorimeter with water, and subtracts these to find the mass of the water.
what did the students do with the ice before adding it to the water?
crushed it up into small pieces and dried it using a paper towel.
how did the student know the ice was at 0C?
it was melting-when a change of state occurs there is no change in temperature
how and why was the ice crushed?
with a pestle and mortar, to ensure all pieces are at 0C (a large lump could be 0c at the surface but cooler at the centre)
how and why was dried ice used?
with a paper cloth, to ensure only solid ice is added and not liquid. adding cooled liquid would affect the energy exchange equation.
how and why was melting ice used?
by allowing the ice to sit out after being crushed-to ensure all the ice is at 0C
describe how the mass of the ice was found
by subtracting the mass of the calorimeter and water from the final mass of the calorimeter, water and melting ice
why did the student use warm water in the experiment?
so that heat loss from the calorimeter when above room temp is balanced by heat entering the calorimeter when it is cooler than room temp
give one precaution that the student took to get an accurate result.
use a sensitive thermometer with a low specific heat capacity.
use an insulating material to minimise heat loss to the surroundings
why was the experiment repeated?
to improve the accuracy of the result.
what was the advantage of having the room temp approximately halfway between the initial and final temp of the water?
so that heat loss from the calorimeter when above room temp is balanced by heat entering the calorimeter when it is cooler than room temp
