How much hydrogen is required to turn 400 g of ice into steam at a temperature of -15

To turn into steam m = 400 g = 0.4 kg of ice at a temperature tо = – 15 ° C, energy is required: Q = Q1 + Q2 + Q3 + Q4, where Q1 is the amount of heat required to heat the ice to the melting temperature t = 0 ° C , Q2 is the amount of heat required to melt ice, Q3 is the amount of heat required to heat water to the boiling point t = 100 ° C, Q4 is the amount of heat required to evaporate water.
one). Heating ice to the melting temperature t = 0 ° C, the amount of heat Q1 = m • c • Δt = 12600 J, where the specific heat capacity of ice c = 2100 J / (kg • deg), temperature change Δt = 0 ° C – (- 15 ° C) = 15 ° C …
2). Melting ice. Q2 = λ • m = 136000 J, where λ = 0.34 MJ / kg = 340000 J / kg is the specific heat of ice melting.
3). Heating water to boiling point t = 100 ° C. Q3 = m • c • Δt = 168000 J, where the specific heat capacity of water c = 4200 J / (kg • deg), temperature change Δt = 100 ° C – 0 ° C = 100 ° C.
4). Water evaporation Q4 = r • m = 920000 J, where r = 2.3 MJ / kg = 2300000 MJ / kg is the specific heat of vaporization. Total: Q = Q1 + Q2 + Q3 + Q4 = 1236.6 kJ
five). To calculate how much hydrogen it will take to burn it, we use the formula Q = q • m, where the specific heat of combustion of the fuel q = 120 MJ / kg. Then m = Q: q = 1236600: 120000000 = 0.0103 kg.
Answer: hydrogen will need 10.3 g.