Question

What is the mass percentage of oxygen in Ba3(PO4)2? Please help how do I go about figuring this out?

Answer 1

Molecular Mass of Compound.

$\\ \sf\longmapsto Ba_3(PO_4)_2$

$\\ \sf\longmapsto 3(137u)+2(39u+4(16u))$

$\\ \sf\longmapsto 411u+2(39u+64u)$

$\\ \sf\longmapsto 411u+2(103u)$

$\\ \sf\longmapsto 411u+206u$

$\\ \sf\longmapsto 617u$

• Molecular mass of O in compound=16(4)=64u

$\\ \sf\longmapsto Mass\%\:of\:O$

$\\ \sf\longmapsto \dfrac{64}{617}\times 100$

$\\ \sf\longmapsto \dfrac{6400}{617}$

$\\ \sf\longmapsto 10.3\%$