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16 Compound X is used by mammals as an alternative energy source to sugars. X is a compound of carbon, hydrogen and oxygen only. (a) Complete combustion of a 2.50 g sample of X in dry oxygen produced 4.31 g of carbon dioxide and 1.32 g of water as the only products. (i) Give a reason why the oxygen used must be dry. (1 (ii) Show that the empirical formula of X is C.H.O. You must show your working. (5