Gypsum is a mineral that is a hydrate of calcium sulfate. The formula of a hydra
ID: 922576 • Letter: G
Question
Gypsum is a mineral that is a hydrate of calcium sulfate. The formula of a hydrate ends in ·nH2O where n equals the moles of water per mole of compound. For example, copper(II) sulfate exists mainly as the pentahydrate, whose formula and crystalline structure are shown at the right.
-- What is the chemical formula of calcium sulfate?
A 1.000 g sample of gypsum contains 0.791 g of calcium sulfate. How many moles of calcium sulfate are in this sample?
Assuming that the remainder of the mass in the sample is water, how many moles of water are in the sample?
-- What is the complete chemical formula for gypsum? (1 point) HINT: use your results from (b) and (c), recognizing that the "n" in the hydrate formula represents the moles of water per mole of compound.
: What is the complete chemical chemical name for gypsum? HINT: use the copper sulfate name as a model
B--Phosphoric acid can be prepared by reaction of sulfuric acid with “phosphate rock” according to the UNBALANCED equation:
Ca3(PO4)2 + H2SO4-----> CaSO4 + H3PO4
Balance the equation by putting the correct coefficients in front of each compound in the reaction. (1 point)
Suppose the reaction is carried out starting with 129 g of Ca3(PO4)2 and 97.4 g of H2SO4. Which substance is the limiting reactant? Explain your reasoning, using calculations as needed. (4 points)
Explanation / Answer
Calcium Sulfate -> CaSO4
0.791 grams of CaSO4 (1mol/136.14g) = 0.0058 moles
0.209 grams of H2O (1mol/18g) = 0.01161 moles
Gypsum -> CaSO4 2H2O, Calcium sulfate dihydrate.
Ca3(PO4)2 + 3H2SO4 -> 3CaSO4 + 2H3PO4
129 g of Ca3(PO4)2 * (1mol/310.18g) = 0.4159 moles
97.4 g of H2SO4 * (1mol/98.079g) = 0.993 moles
Limiting reactant is sulfuric acid, due to it appears in less amount of moles, and reaction will stop due to this.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.