The latent heat of fusion for ice is 6.0 kJ/mole. In order to melt 36 g of ice (solid #H_2O#) at 0°C, how much energy is required?
The molar latent heat of fusion, which is an alternative name given to the enthalpy of fusion, tells you how much heat is required in order to convert a specific amount of a given substance, either a gram or a mole, from solid at its melting point to liquid at its melting point.
Ice is said to have a molar enthalpy of fusion equal to
#DeltaH_"fus" = "6.0 kJ mol"^(-1)#
This means that in order to melt
Now, your sample of ice has a mass of
#36 color(red)(cancel(color(black)("g"))) * ("1 mole H"_2"O")/(18.015color(red)(cancel(color(black)("g")))) = "1.998 moles H"_2"O"#
You can now use the molar enthalpy of fusion as a conversion factor to help you figure out how much heat must be supplied to your sample
#1.998 color(red)(cancel(color(black)("moles ice"))) * "6.0 kJ"/(1color(red)(cancel(color(black)("mole ice")))) = color(darkgreen)(ul(color(black)("12 kJ")))#
The answer is rounded to two sig figs.