Originally posted by zhchem at 2011-07-13 21:10:51:
Exact Mass是准确分子量，一般精确到小数点四位

Molecular Weight指分子量，为整数或者小数点一位

Originally posted by w87437985 at 2011-07-13 21:52:17:
Exact Mass是准确分子量，
Molecular Weight指摩尔分子量，计算了同位素按照其丰都后的平均量。

Originally posted by mddmct at 2011-07-13 22:13:40:
如果有具体例子介绍一下就更好了

Originally posted by w87437985 at 2011-07-13 22:27:33:
HBr
Exact Mass: 79.93
Mol. Wt:80.91
m/e:79.93(100%),81.92(97.3%)

以79的溴为100%的话，81的溴为97.3%，加权平均则为HBr 80.91.