C5H602+O2 ---> CO2+H2O
what is the coefficient of O2?
C5H602 + O2 ---> CO2+H2O
start with C
C5H602 + ? O2 ---> 5 CO2+ ? H2O
now H
C5H602 + ? O2 ---> 5 CO2+ 3 H2O
10 + 3 = 13 O on right
so
need 11 O from O2
so
C5H602 + 5.5 O2 ---> 5 CO2+ 3 H2O
so double everything to get rid of fraction
2C5H602 + 11 O2 ---> 10 CO2+ 6 H2O
so
11