Calcium sulfate, , is a white, crystalline powder. Gypsum is a mineral, or natural substance, that is a hydrate of calcium sulfate. A 1.000-g sample of gypsum contains 0.791 g . How many moles of are there in this sample? Assuming that the rest of the sample is water, how many moles of are there in the sample? Show that the result is consistent with the formula .