Calculate the stoichiometric oxygen required for the combust

Calculate the stoichiometric oxygen required for the combustion of ethanol n C2H5OH + mO2 ==> kH2O + pCO2

a. 1.2g O2 per gram ethanol

b. 1.87 g O2 per gram ethanol

c. 1.63 g ethanol per gram O2

d. 2.09 g O2 per gram ethanol

e. none of the above

Please show work as to correct answer or no rate will be given

Solution

using conservation of C, 2n = p.

conservation of H, 6n = 2k

conservation of O, n + 2m = k + 2p

n + 2m = 3n + 4n, hence m = 3n, so for each mole of ethanol, 3 moles of O2. Hence 1 gram of ethanol = 1/46 moles of ethanol = 3/46 moles of O2 = 3/46 * 32 = 2.09g (D)