You need 16,700 J to melt that much ice at #0^@"C"#.
Since you're dealing with a phase change, the equation you'll need to use is
#q = m * DeltaH_"fus"#, where
#q# - the heat you need to suplly to the ice;
#m# - the mass of the ice;
#DeltaH_"fus"# - the latent heat of fusion, or enthalpy of fusion, which is the change in enthalpy you get when you heat a gram of a substance to change it from solid state to liquid state.
In your case, you need to supply 334 J for every 1 gram of ice at #0^@"C"# to get it to melt it to water at #0^@"C"#. Since you've actually got 50.0 g of ice, the energy required to melt the ice will be
#q = m * DeltaH_"fus"#
#q = 50.0cancel("g") * "334 J" = color(green)("16,700 J")#
