Question

complete combustion of 4.60 g of a hydrocarbon produced 14.1 g of CO2 and 6.73 g of H2O. What is the empirical formula of the hydrocarbon

Answer 1

Given,

Mass of hydrocarbon = 4.60 g

Mass of CO₂ produced after combustion = 14.1 g

Mass of H₂O produced after combustion = 6.73 g

Calculating the number of moles of C and H produced from the given masses of CO₂ and H₂O,

= 14.1 g CO₂ x ( 1 mol / 44.01 g) x ( 1 mol C / 1 mol CO₂)

= 0.3204 mol of C

Similarly,

= 6.73 g H₂Ox ( 1 mol / 18.02 g) x ( 2 mol H / 1 mol H₂O)

= 0.7469 mol of H

Now, Dividing each mole by least number of moles and multiplying by a number to get the whole number of mol.

0.3204 mol of C / 0.3204 mol = 1 mol of C x 3 = 3 mol of C

0.7469 mol of H / 0.3204 mol = 2.33 mol of H x 3 = 7 mol of H

Thus, the empirical formula of the hydrocarbon is C₃H₇