mole fraction

例句：

1. 1.The mole fraction of water in the solution is 0.5.
   溶液中水的摩尔分数为0.5。
2. 2. The mole fraction of oxygen in the gas is 0.25.
   气体中氧气的摩尔分数为0.25。
3. 3. The mole fraction of carbon dioxide in the mixture is 0.4.
   混合物中二氧化碳的摩尔分数为0.4。