M(CH4)=16g/mol n(CH4)= 2 g / (16g/mo l)= 0.125 mol 甲烷的分子个数为N(CH4)=0.125 NA 每个甲烷含4个氢原子, N(H)= 0.125NA * 4=0.5 NA 即得方程： 0.5 NA =X NA=2X 即阿伏加德罗常数是2X
