M(C8H18)=8*12g+18*1g=114g
M(CO2)=12g+2*16g=44g
M(H2O)=2*1g+16g=18g
2C8H18+25O2-->16CO2+18H2O
2*114g C8H18----------------16*44g CO2
5g C8H18 ---------------------------xg CO2
xg=5g*704g/228g
xg=15,4g CO2
2*114g C8H18----------------18*18g H2O
5g C8H18 ---------------------------xg H2O
xg=5g*324g/228g
xg=7,1g H2O