Question

For a crystal with formula BaCl2.xH2O, a student conducted a gravity experiment and found out that 2.44 gram of this crystal can lost mass 0.36 gram when heated to 150 degree. Suppose water is the only reason of weight loss, what is the x value here? (Molar mass of BaCl2 is 208 g/mole and H2O is 18 g/mole.

Answer 1

2.44 g = mass BaCl2 + xH2O
-0.36 g = mass H2O
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2.08 g = mass BaCl2

mols BaCl2 = 2.08/208 = 0.01
mols H2O = 0.36/18 = 0.02
BaCl2.2H2O