(1) How many grams of copper, cu are there in 2.55 mol of cu? (2) Determine the percent composition of each of the following (a) ethylalcohol CH3CH2OH. (b) vitamin C, ascorbic acid C6H8O6. (c) Coteine, C18H21NO3. (3) A 27.5g sample of a compound containing carbon and hydrogen contains 5.5g of hydrogen. What is the empirical formula of this compound. (4) How many moles of gallium chloride are formed by the reaction of 1.5mol of HCL according to the following equation. 2Ga + 6HCL = 2GaCl3 + 3H2