The molar mass should be 14.898g/mol. I used the equation 100gx(1/xg/mol)x(1mol/2mol)x(16g/mol+x)/1)=103.7 and solve for x. I found that equation using stoichiometry and the equation 2m+1/2O2-->m2O The molar mass of the metal I set to x and the molar mass of the metal oxide is 16+x.