Alum problem?

Question

Any help with the following problem will be appreciated thanks!
the molecular mass of KAl(SO4)2*12H2O is 474.22g

Given the following equation

KAl(SO4)2*12H2O+ 2BaCl2 ----> KCl + AlCl3 + 2BaSO4+ 12H2O

What is the percent yield of barium sulfate if 1.02 grams is produced?

If a 10 gram sample of alum is heated to drive off all of the water of the solid. determine the mass of the dehydrated alum.

Answer 1

The first part of the problem cannot be answered, because you don't give the starting amounts either of BaCl2 or alum*12H2O.

For the second part, atomic weights: K=39 Al=27 SO4 2-=96 KAl(SO4)2=258

Let the hydrate be called H. Let the dehydrated be called D.

10gH x 1molH/474gH x 1molD/1molH x 258gD/1molD = 5.4g

The10gH is given. The next factor comes from the formula weight of H. The next factor comes from the balanced equation. The next factor comes from the formula weight of D.