What is the mass percent of oxygen in Al2(SO4)3·18H2O? Molar mass Al2(SO4)3·18H2O is 666.43 g/mol (A) 9.60 (B) 28.8 (C) 43.2 (D) 72.0
molar mass of oxygen is 16g/mol.
There are 30 oxygen moles inside 1mol of the compound `Al_2(SO_4)_3·18H_2O`
Mass of Oxygen in the compound `= 30xx16 = 480g`
Mass % of oxygen `= 480/666.43xx100% = 72%.`
So mass percentage of oxygen in `Al_2(SO_4)_3·18H_2O` is 72%.
The correct answer is at D)