A compression ignition engine operates with a liquid fuel that has an unspecified molecular formula C1HO. Analysis shows that the fuel contains 52% carbon, 13% hydrogen and 35% oxygen on a mass basis. Assume that no EGR is used. Emission test is conducted on this engine and the following measurements are collected:

Engine power	220 kW
Air flow rate	320 g/s
Excess air ratio	1.6
Tail-pipe NOx emissions	50 ppm by volume

Calculate the following and provide your answer in the indicated units: (1) The value of and in the fuel molecular formula (2) Stoichiometric air-fuel ratio (by mass) for the given fuel [-] (3) Fuel flow rate [g/s] (4) Power based NO₂ emissions [g/kWh] (Hint: Assume air density is 1.29 kg/m3, power-based emission is defined as the mass of emission produced when the engine generates 1 kWh energy)