首先,分母要从1000ml变成100ml,体积缩小了10倍所以质量也要缩小10倍,即分子要除以10,分母要变成100ml2mg/1000ml就变成了0.2mg/100ml100ml里面就有0.2mg1000mg=1g,1mg=0.001g,所以0.2mg=0.0002g所以100ml里面有0.0002g即0.0002g/100ml望采纳,谢谢
1mg=0.001g2mg/1000m=0.02g/100ml