Question

If 2.09 mol of ethane (C₂H6) undergo combus-

tion according to the unbalanced equation
C₂H6+ O2 CO₂ + H₂O,
how many moles of O₂ is required?
Answer in units of mol. Answer in units of
mol.

Answer 1

7.32 moles of O2

For every mole of C2H6 you’ll get 2 moles of CO2 and 3 moles of H2O

We know this because the carbon and hydrogen has to be equivalent on both sides.

2.09 * 2 = 4.18 moles of CO2
2.09 * 3 = 6.27 moles of H2O

4.18 * 2 + 6.27 = 8.36 + 6.27 = 14.63 moles of O
14.63/2 = 7.32 moles of O2