Question

If you want to heat 100 kg of water at 20 ° C for your bath, calculate the amount of heat in the water. Then demonstrate that this is equivalent to 8360 kilojoules.

20° C x 100 kg = 2000000 cal

I'm unsure what to do after converting it to calories as to demonstrate the equivalent to joules

Answer 1

I do not know where to start.

20 Cs is about room temperature so you must be heating it to some higher temperature:
You need a temperature DIFFERENCE

heat in = Sh * mass * change in temp

in Kilocal /kilogram deg C , Sh water is 1.00 indeed
so you have
heat in = 1 *100 * (Temp - 20)
KILOCALORIES

1 kilocalorie = 1.484 kilojoules
so
multiply by 1.484 to get kilojoules

By the way if it is 8360 kilojoules that is 8360/1.484 = 5633 kilocalories
so 56.33 = T-20
so that bath water temp must have been 76.33 deg C but that is doing the problem backwards