Answer: There are 0.056 moles present in 3.45 g of [tex]Na_{2}O[/tex].
Explanation:
Given : Mass = 3.45 g
Moles is the mass of substance divided by its molar mass.
Hence, moles of [tex]Na_{2}O[/tex] (molar mass = 61.98 g/mol) is as follows.
[tex]Moles = \frac{mass}{molar mass}\\= \frac{3.45 g}{61.98 g/mol}\\= 0.056 mol[/tex]
Thus, we can conclude that there are 0.056 moles present in 3.45 g of [tex]Na_{2}O[/tex].