Answer:
56.26%
Step-by-step explanation:
The theoretical mass percent of barium in BaCl2 . 2H2O can be calculated as follows:
First, find the molar mass of BaCl2 . 2H2O:
BaCl2 . 2H2O = Ba + 2Cl + 2(H2O)
= 137.327 + 2 x 35.45 + 2 x 18.015
= 244.297 g/mol
Next, find the mass of barium in one mole of BaCl2 . 2H2O:
Ba = 137.327 g
Finally, divide the mass of barium by the total mass and multiply by 100:
(137.327 g / 244.297 g) x 100% = 56.26%
So, the theoretical mass percent of barium in BaCl2 . 2H2O is 56.26%.