關於chem

1 mole of air
= 0.21 (mass of oxygen) + 0.79 (mass of nitrogen)
= 0.21 x 16x2 + 0.79 x 14x2
= 28.84g

1 mole of nitrogen
= 14 x 2
= 28g
therefore, nitrogen gas is slightly lighter than air. The balloon fills up with nitrogen and it only rises up a little bit or doesn't rise up. Nitrogen is not suitable for rising ballo0n

Air contains roughly (by molar content/volume) 78% nitrogen, 20.95% oxygen, 0.93% argon, 0.038% carbon dioxide, trace amounts of other gases,

輕氣球明顯地需要較molecular mass輕的氣體才能升起，既然大氣含７８％氮，你用氮充氣並不能令氣球上升．
要找molecular mass較輕的氣體不難，參照”元素表”

lt is because nitrogen is oxiding