Answer:
12.1 grams and 77.8%
Step-by-step explanation:
(Note: in this answer, sig figs are rounded in the end, not along the way) The molar ratio of calcium sulfate to calcium hydroxide is 1:1
there are 6.56 grams of calcium hydroxide, so the number of moles is the number of grams / the molar mass, which is (6.56 grams) / (74.093 g/mole)
=0.08854 moles of calcium hydroxide
Theoretically, 0.08854 moles of calcium hydroxide would make 0.08854 moles of calcium sulfate.
To find the number of grams of calcium sulfate, multiply the number of moles by the molar mass, which is .08854 * 136.14 = 12.054 grams, or
12.05 grams
The percentage yield of calcium sulfate is just the actual yield / predicted yield, which is 9.37/12.05 which is 0.7776, or 77.8%