what is the enthalpy of combustion of a compound if its enthalpy of formation is -520 kJ/mol and if the total enthalpy of formation is its products is -670 kJ/mol (adjusted for the coefficients )?

Liquid from a brewery fermentation contains 10% ethanol and 90% water. part of the fermentation product (50,000 kg/h) is pumped to a distillation column on the factory site. under current operating conditions, a distillate of 45% ethanol and 55% water is produced from the top of the column at a rate of one-tenth that of the feed. what is the composition of the waste "bottoms" from the still?