Molar mass of Al2(SO4)3 = 342.15g/mol
[tex]7.20gAl2(SO4)3 * \frac{1mol}{342.15g} = .0210434mol[/tex]
[tex].0210434molAl2(SO4)3* \frac{12molO}{1mol} = .25252mol O[/tex]
Molar mass of O = 15.9994g/mol
[tex].25252molO* \frac{15.9994g}{1mol} = 4.04g O [/tex]
