mole of electron

例句：

1. 1. The mole is the smallest unit of measurement for matter.
   摩尔是物质最小的计量单位。
2. 2. The mole ratio is used to calculate the amount of a substance in a solution.
   摩尔比用于计算溶液中物质的量。
3. 3. The mole fraction of a compound is the ratio of its molecules to the total number of moleculesin the mixture.
   化合物的摩尔分数是其分子数与混合物总分子数的比例。