ta co:nc (so mol cacbon)=0.5 g va mc=6g dan den so mol H nguyen tu =2..........xet X phan ung Br2
gia su Xco 1 lien ket pi dan den nX=0.25 dan den X laC2H4 vua van H khong con H2 nguyen tu(loai)
...............2...............................0.125.................C4H6 vz con 0.625mol H2(thoa...