XO+O--->XO2
m(XO)=10.00g
M(XO)=16+[M(X)]
m(XO2)=15.33g
M(XO2)=32+[M(X)]
n(XO):n(XO2)
=1:1
.: 10/(16+[M(X)]) = 15.33/(32+[M(X)])
16+[M(X)] = (320+10*[M(X)] )/15.33
15.33*M(X) = 74.72+10*M(X)
5.33*M(X) = 74.72
M(X)=14.018=14.02g/mol
So, relative atomic mass of X is 14.02g/mol making it nitrogen
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