Answer:
66,3 g of MgSO₄· 7 H₂O
Step-by-step explanation:
Some salts must be hydrated to increase solubility.
Magnesium sulfate heptahydrate has as molecular formula
MgSO₄· 7 H₂O
The molecular weight is the sum of atomic weights. Thus:
1 Mg × (24,305 g/mol) = 24,305 g/mol
1 S × (32,065 g/mol) = 32,065 g/mol
11 O × (15,999 g/mol) = 175,989 g/mol
14 H × (1,008 g/mol) = 14,112 g/mol
Molecular weight: 246,471 g/mol
269 mmol are 0,269 mol (m is mili: 1×10⁻³. It means 269×10⁻³ = 0,269)
0,269 mol of MgSO₄· 7 H₂O × (246,471 g / mol) = 66,3 g of MgSO₄· 7 H₂O
I hope it helps!