Water heater contains 56 part a how many kilowatt-hours of energy are necessary to heat the water in the water heater by 25? c?

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.