Consider the following 2 types of coal samples. Y, Z and compare based on i) calorific value ii) water content. B) Also estimate the minimum weight and volume at STP of air necessary for complete combustion of 1kg of the coal sample Y. Y) C=76% H=10%, S=5% and O=9% Z) C=82%, H =8%, S=4% and O=6% (NB: The percentages are mass percent)