|
Answer» Percentage of OXYGEN in air is 80%
percentage = VOLUME of the oxygen/volume of air ×100
80 = volume of oxygen/1L × 100
80L × 1/100 = volume of oxygen
0.8L = volume of oxygen
[or you can directly do it like in 1L air percentage of oxygen is 80 MEANS 0.8L oxygen and 0.2L other substance]
_____________________________________________________
We KNOW that one mole of any substance CONTAINS 22.4L volume in STP (standard temperature and pressure) so,
volume = number of moles ×22.4
volume/22.4 = number of moles
0.8/22.4 = number of moles
0.036 = number of moles
______________________________________________
we know that one mole of any substance contains 6.022×10^23 molecules.
molecules = number of moles × 6.022×10^23
molecules = 0.036 × 6.022 × 10^23
molecules = 0.216 × 10^23
molecules = 2.16 × 10^22 " O2 molecules ”
_______________________________________________
use can directly find it use this formula
molecules = volume of substance/22.4 × 6.022×10^23
|
