Posted by James on .
A 64.8 g mixture of the compounds potassium sulfide and calcium oxide is 17.1 % by mass potassium sulfide. The compound calcium oxide is 71.5 % by mass calcium. Calculate the mass (g) of oxygen in the mixture.
mass % = mass part/mass whole x 100.
I attempted the problem by subtracting 100 - 71.5 or 1 - .715 to get oxygen, and multiplied by the given mass. I'm stuck :(