(C${}_6$H${}_{10}$O${}_5$)${}_n$ → nC${}_6$H${}_{12}$O${}_6$ → 2nC${}_2$H${}_5$OH
mC${}_2$H${}_5$OH = 23.30%.0,8 = 5,52 kg
→ a = 5,52.162/(2.46.80%.75%) = 16,2 kg