A sample of hydrated magnesium sulfate, MgSO4⋅xH2O\text{MgSO}_4 \cdot x\text{H}_2\text{O}MgSO4⋅xH2O, has a mass of 4.93 g. After heating to constant mass to remove all water of crystallisation, the anhydrous residue has a mass of 2.41 g.
What is the value of xxx?
[Relative atomic masses, ArA_rAr: H=1.0\text{H} = 1.0H=1.0, O=16.0\text{O} = 16.0O=16.0, Mg=24.3\text{Mg} = 24.3Mg=24.3, S=32.1\text{S} = 32.1S=32.1]
222
555
666
777
