The percent of O in Cr₂O₃ : 31.58%
Given
Cr = 52.00 amu, O = 16.00 amu
Required
The percent of O
Solution
MW Cr₂O₃ = 2 x Ar Cr + 3 x Ar O
MW Cr₂O₃ = 2.52+3.16
MW Cr₂O₃ =152 amu
[tex]\tt \%O=\dfrac{3.Ar~O}{MW~Cr_2O_3}\times 100\%\\\\\%O=\dfrac{3.16}{152}\times 100\%\\\\\%O=31.58\%[/tex]