As a consequence, many of these products are ineffective,sub-standard, and in some cases dangerous.

VOA: standard.2010.03.09

In other words, we choose a convention for the zero of entropy, so that then we can write entropies of products and reactants always referring to the same standard state.

换句话说，我们选择了一个,焓零点的约定，这样我们,就可以总是相对于同样的标准,状态写出生成物和反应物的焓。

麻省理工公开课 - 热力学与动力学课程节选