## Chemistry: An Atoms-Focused Approach

(a) In one mole of NaCl, we have 1 mole of sodium. (b) In one mole of Na$_2$SO$_4$, we have 2 moles of sodium. (c) In one mole of Na$_3$PO$_4$, we have 3 moles of sodium. (d) In one mole of NaNO$_3$, we have 1 mole of sodium.