1st - molar mass is 315.4 gram per mol, not 315.4 mol. 2nd - you didn't tell how many moles is 3.9g, but according to your concentration calculations you have found it to be 0.02276 mole - which is wrong. 3rd - barium hydroxide dissociation ends up with OH-ions, not H+- so you...
Finding molar mass starts with units of grams per mole (g/mol). When calculating molecular weight of a chemical compound, it tells us how many grams are in one mole of that substance. The formula weight is simply the weight in atomic mass units of all the atoms in a given formula....