How many joules of heat are required to melt 40kg of ice at 0 degrees celsious?

Answer 1

Note that Celsius is the correct spelling.
q = mass x heat fusion.
Look up the heat of fusion for ice (in joules/g). You have the mass. Calculate q, the heat required to melt the ice. Be careful that specific heat you use doesn't conflict with the units for mass.

Answer 2

The heat of fusion of ice is 4180 J/kg.

Multiply that by the mass that is melting