test 空氣中氧佔的百分比

如何利用一支硬玻璃管裝填碎銅片測試空氣中氧佔的百分比?
first, you have to put the copper into the test tube. Then you have to heat the test tube which contain known amount of air. while you are heating the air, copper inside would react with the oxygen in air to form copper (II) oxide. then you have to draw all the air (without oxygen) out with a syringe to measure the air remains,then you will know the percentage of oxygen in air.

點解要等碎銅片凍左之後先可以記錄新的體積係幾多？
because air would expand on heating, you have to measure the volume of the air left when it is cooled sufficiently in order to have a correct percentage of oxygen

係唔係一加熱，ｄ碎銅片就會吸哂ｄ氧？
no,you are wrong. the copper react with oxygen not absorb the oxygen