@ionxken: This question is really testing whether you know the composition of air. Air is roughly 79% nitrogen, 21% oxygen, 1% other gases. Heated iron reacts with oxygen to form iron oxide, a solid. So the oxygen gets removed from the gas and the volume drops. “No further decrease” means all the oxygen is gone. What’s left is the nitrogen and the inert gases, so 79% of the original 80 cm3. Two traps. Cooling back to the original temperature is there so you can’t blame the volume change on expansion. And the iron oxide is solid, so it adds nothing back to the gas volume #creatorsearchinsights #ionxlabs #airandatmosphere #olevelchemistry #purechemistry

Ken | IONX Labs

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Wednesday 16 September 2026 15:59:40 GMT