Question

What mass of nitrogen (in milligrams) is there in 30. mg of capsaicin?

Answer 1

"Mass percent of oxygen in capsaicin is 15.72 percent."

It means

when you take mass of the whole thing,

and the mass of just the oxygen in it,

The mass of oxygen will be 15.72% of the whole.

???

Find 15.72% 30mg.

Answer 2

Mass of nitrogen is there in 30.mg of capsaicin is 15 .72 %