00:01
All right, so let's say we have a liquid that has a mass of 0 .3 kilograms, initially at a temperature of 200 degrees celsius, and we want to cool it down to 50 degrees celsius, but undergoing a phase transition in the process.
00:15
We want to know how much energy would be required, or how much energy has to be removed from the sample for this to work.
00:23
So it'll be m times the heat capacity, times the temperature change to the freezing temperature.
00:30
Point we'll call this delta t f plus m times the latent heat of fusion and then plus m times the heat capacity in the solid state times the final temperature change so this is we'll call c l like for the liquid so we can write we can factor the m out of all of this which is 0 .3 kilograms and we're told the heat capacity in the liquid state is 900 jules per kilogram per degree celsius.
01:03
The temperature change is going to be 100 degrees celsius, and then plus the latent heat of fusion, which we're told is 10 ,000 joules per kilogram.
01:16
And then finally, plus 770 joules per kilogram per degree celsius times an additional 50 degrees celsius, because that's the temperature.
01:27
We're going to 50 times 770 plus 10 ,000 plus 900 times 100 times 0 .3...