I said mass because kilograms is actually a unit of mass.

我说质量是因为千克实际上是一个质量单位。

So then we convert 0.288 moles of sodium chloride into units of mass and grams.

因此，我们将 0. 288 摩尔氯化钠转换为质量和克的单位。

Basically over a 20 year period, methane can be 84 times as powerful per unit of mass as carbon dioxide, so it has the muscle to be as threatening as CO2.

基本上在 20 年的时间里，甲烷每单位质量的威力是二氧化碳的 84 倍，因此它具有与二氧化碳一样具有威胁性的力量。