Answer is: 550,021 kWh of energy is needed to heat the water
V(water) = 51 gal = 51·3,78 = 189,3 L.
ΔT(water) = 25°C.
d(water) = 1000 g/L.
m(water) = V(water) · d(water)
m(water) = 189,3 L · 1000 g/L
m(water) = 189300 g.
Q = m(water) · ΔT(water) · C(water)
Q = 189300 g · 25°C · 4,184 J/°C·g
Q = 19800780 J = 19800,78 kJ ÷ 3600 = 550,021 kWh.
