J.R. S. answered • 08/13/19

Ph.D. University Professor with 10+ years Tutoring Experience

Since the unknown contains only C and H, we can calculate moles of C from the CO_{2}and moles of H from the H_{2}O.

1.6 g CO_{2} x 1 mol CO_{2}/44 g = 0.0363 moles CO_{2 }x 1 mol C/mole CO_{2} = 0.0363 moles C

0.819 g H_{2}O x 1 mole/18 g = 0.0455 moles H_{2}O x 2 moles H/mol H_{2}O = 0.091 moles H

Dividing both by 0.0363 to get a whole number for moles of C, we get 1 mole C and 2.5 moles of H. If we now multiply by 2, we get

2 moles C and 5 moles of H. Empirical formula thus is

C_{2}H_{5}