You need an additional point of data here: the enthalpy of fusion, or conversely the enthalpy of melting (they differ only by their sign). For water (or ice) that value is gotten from sources such as the internet
ΔH°(fus) = 6.01 kJ/mole
Since you have 35 000g, how many moles do you have?
Moles H2O = 35000 g/(18.015 g/mole) = 1942.8 moles
So, take that ΔH°(fus) in kJ/mole, multiply by the number of moles, and there ya go!
6.01 x 1942.8 = 11,676 kJ of energy is released
Hope I helped!! xx
