— Earth's atmosphere ⇒ blanket of gas around the earth 700km thick
90% of the Earth's mass → the first 16km
the first 1-10km ⇒ toposphere
— air is:
78% nitrogen
21% oxygen
1% argon, carbon dioxide, other noble gases
— water vapour
— sulfur dioxide
— carbon monoxide
— CO2 → plants
— N2 → dilutes oxygen
— O2 → respiration ⇒ glucose + oxygen → carbon dioxide + water
— push the volume of air from A to B
— continue and the volume will change, reacting with the copper
— continue until the volume no longer changes (all the oxygen is used up — reacted)