#### Answer

(a) 1 mole of N$_2$O$_5$
(b) 1 mole of Ca(NO$_3$)$_2$
(c) 2 moles of NO$_2$

#### Work Step by Step

(a) Two moles of N$_2$O$_3$ has 4 moles of oxygen. One mole of N$_2$O$_5$ has 5 moles of oxygen. Therefore, 1 mole of N$_2$O$_5$ has more moles of oxygen than 2 moles of N$_2$O$_3$.
(b) One mole of NO has 1 mole of oxygen. One mole of Ca(NO$_3$)$_2$ has 6 moles of oxygen (multiply the subscript for O with the subscript outside of the parentheses). Therefore, 1 mole of Ca(NO$_3$)$_2$ has more moles of oxygen than 1 mole of NO.
(c) Two moles of NO$_2$ have 4 moles of oxygen. One mole of NaNO$_2$ has 2 moles of oxygen. Therefore, 2 moles of NO$_2$ have more moles of oxygen than 1 mole of NaNO$_2$.