Thank you Damon! now, here's the last part of that along with the first again....
Calculate the height from which a block of ice at zero degrees celcius nust be dropped for it to completely melt upon impact. Assume that there is no air resistance and that all the energy goes into melting the ice.
Equate the joules of gravitational potential energy to the product of the mass of ice and its heat of fusion (in SI units, 335,000 J/kg.) Do you see why the answer doesn't depend on mass?
I answered this below when you first asked.
The mass cancels.