Answer
(a) Both compounds have the same number of moles of oxygen.
(b) 1 mole of N$_2$O$_4$
(c) 2 moles of CO$_2$
Work Step by Step
(a) One mole of Al$_2$O$_3$ has 3 moles of oxygen. One mole of Fe$_2$O$_3$ has 3 moles of oxygen. Therefore, both compounds have the same number of moles of oxygen.
(b) One mole of SiO$_2$ has 2 moles of oxygen. One mole of N$_2$O$_4$ has 4 moles of oxygen. Therefore, 1 mole of N$_2$O$_4$ has more moles of oxygen than 1 mole of SiO$_2$.
(c) Three moles of CO have 3 moles of oxygen. Two moles of CO$_2$ have 4 moles of oxygen. Therefore, 2 moles of CO$_2$ have more moles of oxygen than 3 moles of CO.
