Hydrogen $($H$2)$ gas is burned in an isobaric steady$-$flow burner with $81\%$ excess air. The air and fuel enter the burner at $25\backslash$deg C and the combustion products leave at $727\backslash$deg C$.$ Assuming that the water leaving the burner is in the vapour phase, calculate how much heat in kJ per $1$ kg of fuel is released when combustion is complete? Provide the answer to five significant figures