[tom.leniston]

Calculate the mass of oxygen in a human body with 80kg weight!
With explanation

[sjb]

Any thoughts of your own. What compounds are there in the body that contain oxygen?

[tom.leniston]

Any thoughts of your own. What compounds are there in the body that contain oxygen?

Gases such as oxygen, carbon dioxide, nitrogen oxide, hydrogen, carbon monoxide, acetaldehyde, formaldehyde, methanethiol. These may be dissolved or present in the gases in the lungs or intestines.
WATER ..

[Babcock_Hall]

Neither hydrogen gas, nor methanethiol have any oxygen atoms.  One thing that could stand a bit of clarification:  Are we talking only about molecular oxygen, or are we talking about element oxygen, which can be found in water, sugars, etc.?

[tom.leniston]

Neither hydrogen gas, nor methanethiol have any oxygen atoms.  One thing that could stand a bit of clarification:  Are we talking only about molecular oxygen, or are we talking about element oxygen, which can be found in water, sugars, etc.?

Molecular oxygen

[Babcock_Hall]

It is a Forum Rule (see red link) that you must show your attempt before we can help you.  What have you come up with, so far?

[Corribus]

A good place to start is: where is oxygen most likely to be in the body, and how might you go about estimating how much is there?