CHEM QUEST

Chemical formula of nitrogen is N2, which implies one nitrogen molecule is made up of two nitrogen atoms.
Mass of nitrogen gas = 4g
Molar mass of nitrogen gas = 2 X 14.0 = 28 g/mol
No. of mole of nitrogen
= Mass / Molar mass
= 4 / 28
= 1 /7 mol

On the other hand,
Chemical formula of oxygen is O2, which implies one oxygen molecule is made up of two oxygen atoms.

Mass of oxygen gas = 64g
Molar mass of oxygen gas = 2 X 16.0 = 32 g/mol
No. of mole of oxygen = Mass / Molar mass
= 64 / 32
= 2 mol
By Avocado's Law, all gases occupies the same volume in the room conditions. (i.e. 24 dm^3 / mol)
That is, no. of molecules presented in 64g of oxygen gas
= 2 / (1 / 7) y
= 14y

我諗架咋...
我覺得個答案系14y or 1.204x10既24次方

y的值:
6.02x10既23次方 乘 4除(14x2)
y=8.6x10既22次方

molecules of oxygen gas :
6.02x10既23次方 乘 64 除 (16x2)
=1.204x10既24次方

1.204x10既24次方 除 8.6x10既22次方 = 14
so = 14y

希望岩! =]