How much energy needs to be spent to melt ice weighing 4 kg at a temperature of 0 degrees.

m = 4 kg.
λ = 3.4 * 10 ^ 5 J / kg.
Q -?
The amount of heat energy Q, which must be expended to melt ice at the melting temperature, is determined by the formula: Q = λ * m. Where λ is the specific heat of fusion of the substance, m is the body mass.
Q = 3.4 * 10 ^ 5 J / kg * 4 kg = 13.6 * 10 ^ 5 J.
Answer: to melt ice you need Q = 13.6 * 10 ^ 5 J of thermal energy.