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