233.54 g is the mass of the oxygen.
Mass of any element in the compound can be given as the product of the number of moles of the element in the compound and the molar mass of the element.
How to calculate the mass of the oxygen?
We know that,
The atomic weight of oxygen = 16 g
Mass of the [tex]\rm Na_{2}O[/tex] = 61.97 g/mol
1 mole [tex]\rm Na_{2}O[/tex] = 1 mole of O
[tex]\begin{aligned}&=\dfrac{905\;\rm g }{62\;\rm g/mole} \\\\&= 14.59\;\rm moles Na_{2}O \end{aligned}[/tex]
So,
Moles O = 14.59
The molar mass of oxygen = 16 g
Mass can be calculated as:
[tex]\begin{aligned} \rm mass &= \rm molar \;mass \times \rm moles \\\\&= 14.59 \times 16\\\\&= 233.54 \;\rm g\end{aligned}[/tex]
Therefore, 233.54 g is the mass of the oxygen in the [tex]\rm Na_{2}O[/tex].
Learn more about moles and mass here:
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