144 grams of C5H12 is burnt with 64 grams O2, and 44 grams of

144-grams-of-c5h12-is-burnt-with-64-grams-o2-and-44-grams-of

144 grams of C5H12 is burnt with 64 grams O2, and 44 grams of CO2 is formed, what is the percentage of excess O2?
A. 25%
B. 50%
C. 75%
D. 100%
Correct option is A. 25%

The balanced chemical reaction is C5H12 + 8O2 -> 5CO2 + 6H2O, => Extent of reaction = (44/44 – 0)/5 = 0.2. Moles of O2 entered the process = 64/32 = 2, Moles of O2 required = 0.2*8 = 1.6, => Percentage of excess oxygen = 100*(2 – 1.6)/1.6 = 25%.