Question

how many moles of oxygen atoms are in 125 g of ba3(po4)2?

Answer 1

Number of moles = amount in grams / molar mass

= 125 g of Ba3(PO4)2/ 601.9237 g/mol

=0.208 Mole Ba3(PO4)2

1 mole Ba3(PO4)2  contains 8 mole  oxygen  

Therefore  

0.208 Mole Ba3(PO4)2 * 8 mole oxygen / 1 mole Ba3(PO4)2  

=1.664 mole oxygen  

Answer 2

Answer: 1.6 moles of oxygen atoms

Explanation:-

According to avogadro's law, 1 mole of every substance weighs equal to its molecular mass and contains avogadro's number $6.023\times 10^{23}$ of particles.

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}=\frac{125g}{602g/mol}=0.2moles$

1 mole of $Ba_3(PO_4)_2$ contains = 8 moles of oxygen atoms

0.2 moles of $Ba_3(PO_4)_2$ contain= $\frac{8}{1}\times 0.2=1.6$ moles of oxygen atoms

Thus 1.6 moles of oxygen atoms are present in 125 g of $Ba_3(PO_4)_2$.