\(n_{Br_2}=\dfrac{2,8}{160}=0,0175\left(mol\right)\\ C_2H_4+Br_2\rightarrow C_2H_4Br_2\\ n_{C_2H_4}=n_{Br_2}=0,0175\left(mol\right)\\ m_{C_2H_4}=28.0,0175=0,49\left(g\right)\\ m_{CH_4}=4,3-0,49=3,81\left(g\right)\\ n_{CH_4}=\dfrac{3,81}{16}=0,238125\left(mol\right)\\ \%V_{C_2H_4}=\dfrac{0,0175}{0,0175+0,238125}.100\%\approx6,846\%\\ \%V_{CH_4}\approx93,154\%\)
Câu c hình như chưa đủ đề em hi