How much energy is released when 2.55kg of diethyl ether freezes?

4 answers

You need the latent heat of fusion. You may have been given it with the question.

http://en.wikipedia.org/wiki/Diethyl_ether_(data_page)

has 7.19 kJ mol-1

so calculate the number of moles of diethyl ether relative molecular mass = 74.14

then multiply the number of moles by the latent heat of fusion.
533.0666 kj
How much energy is released when 1.9 kg of diethyl ether freezes? In kj
1. Convert 2.55Kg to g
2.55Kg x 1000g = 2550g
———
1Kg
2. Convert g to mol using the molar mass then multiply the heat of fusion

2550g x 1mol x 7.27KJ = 250 KJ
——— ———-
74.14g 1mol