Calculate the mass fraction of each element in the magnesium sulphate MgSO4

given:
MgSO4
find:
ω(Mg) - ?
ω(S) -?
ω(O) -?
Solution:
Мr(MgSO4) = Аr(Mg) + Аr(S) + 4Аr(O) = 24 + 32 + 4 • 16 = 120
ω(Mg)=Аr(Mg)/Мr(MgSO₄) •100 %= 24/120•100 %  =20 %
ω(S)=Аr(S)/Мr(MgSO₄)   •100 % = 32/120•100 %= 26,7 %
ω(O)=4Аr(O)/Мr(MgSO₄) •100 %  = 64/120•100 %= 53,3 %
Answer:ω(Mg) = 20 %; ω(S) = 26,7 %; ω(O) = 53,3 %.