posted by c .
CaSO4.2H2O ==> CaSO4 + 2H2O
moles CaSO4.2H2O = 15.00 g x (1 mole CaSO4.2H2O/172.172) = 0.08712 moles.
moles CaSO4 = same.
grams CaSO4 = moles CaSO4 x molar mass CaSO4 = ??
Wait,.. how do I know the moles CaSO4?
do I do .08712* CaSO4's gfm?
sorry i'm a bit confused, what are we trying to find?
I recognize this from my post last night. Since you have 0.08712 mole of CaSO4.2H2O AND there is 1 mole CaSO4 per 1 mole CaSO4.2H2O (from the equation), then you must have 0.08712 mole CaSO4.
Then moles CaSO4 x molar mass CaSO4 = grams CaSO4. It's approximately 12 grams.