Đ á p á n B X : - H N C H R C O - n O H : x m o l → X → C O N H : n x m o l C H 2 : y m o l H 2 O : x m o l → O 2 , t O C O 2 H 2 O N 2 n C O 2 = n x + y = b n H 2 O = 0 , 5 n x + x + y = c ( 1 ) b - c = 3 , 5 x ( 1 ) → 0 , 5 n c - x = 3 , 5 x → n = 9 → n - 1 = 8