It will be hard to found the compound molecular weight just by the weight. I can think 2 kind of atom for this configuration.
First, it was NO or nitric oxide. It molecular weight is 16+14= 30. But if you search the exact weight is 30.01 g/mol
Second, it was (CH3)2 or ethane. The molecular weight is 2*12+ 6*1= 30. But if you search the exact weight is 30.07 g/mol. So it more likely to be ethane.
