If 6.49 mol of ethane (C2H6) undergo combustion according to the unbalanced equation C2H6 + O2 −→ CO2 + H2O ,
how many moles of O2 is required?
1. 27.79
2. 7.63
3. 8.4
4. 25.48
5. 12.635
6. 21.035
7. 23.8
8. 19.04
9. 22.715
10. 26.775
Answer in units of mol.

22.715 moles of oxygen are used

Explanation:

Given data:

Number of moles of ethane = 6.49 mol

Number of moles of O₂ required = ?

Solution:

Chemical equation:

2C₂H₆ + 7O₂       →     4CO₂ + 6H₂O

Now we will compare the moles of oxygen with ethane.

                    C₂H₆           :           O₂  

                       2              :             7

                     6.49           :           7/2×6.49 = 22.715 mol

Thus, 22.715 moles of oxygen are used.

the answer is d. 74.02