дано
V(O2) = 20 L
m(C7H16)-?
C7H16+11O2-->7CO2+8H2O
n(O2) = V(O2) / Vm = 20 / 22.4 = 0.89 mol
n(C7H16) = 11n(O2)
n(C7H16) = 0.89 / 11 = 0.08 mol
M(C7H16) = 100 g/mol
m(C7H16) =n*M= 0.08 * 100 = 8г
ответ 8 g
