At the beginning of the summer, the 70.0 m³ of water in a back-yard swimming pool must be heated from 3.27 oC to 22.6 oC. The heat is supplied from a natural gas fired heater and the efficiency of transferring the heat from the combustion reaction to the water is 65%.
The heater generates 30.0 kW of power. How long (in hours) will the heating require?
HINT: The enthalpy of combustion of methane is -803 kJ mol⁻¹. and 1 kW = 1000 J s⁻¹.