Answer:
3. 049g
Explanation:
Molar mass of Ca = 40
Molar mass of Cl = 35.5
H = 1, O =16
Molar mass of CaCl2.9H20 = [40 + (35.5*2) + (9*18)]
CaCl2.9H20 = 273g/mol
Molar mass of CaCl2 = 40 + (35.5*2) = 111g/mol
111g of CaCl2 is present in 273g of CaCl2.9H20
Xg of CaCl2 is present in 7.5g of CaCl2.9H20
X = (7.5*111) / 273
X = 3.049g