Agas contains, by mass, 75% propane (c3h8, molar mass 44 09 g/mol), 20% n-butane (c. h1o, molar mass 58 12 g/mol), and the balance water (molar mass 18 02 g/mol) 41 calculate the molar composition of this gas on both a wet and a dry basis and the ratio (mol h2o/mol dry gas) (10) 4 2 if 100 kg/h of this gas is to be burned with 30% excess air, what is the required air feed rate (kmol/h)? (12) 4.3 how would the answer change of the combustion were only 80% complete?