415 anhydrous barium chloride where obtained when 459 of hydrated salt where heated. calculate n in the formula bacl2 .nh2 o
415 WHAT? 459 WHAT? tons? miles? km? I will assume you meant grams. Also, I assume you meant to write "were" instead of "where".
BaCl2.xH2O ==> BaCl2 + xH2O
459 g.....................415.........x grams
grams H2O in the hydrate = 459 - 415 = 44
mols BaCl2 = grams/molar mass = 415/208.3 = 1.99
mols H2O = 44/18 = 2.44
Then per 1 mole BaCl2 we have 2.44/1.99 = 1.23 moles H2O and the formula would be BaCl2.1.23H2O. You need to look at your data because the accepted value is BaCl2.2H2O.