Question

how many moles of O2 are present in 80% volume of o2 at STP

Answer 1

amount of O2 present in 1 litre of air is
80% × 1000ml
80%=80/100
then,
(80/100)×1000
=800 ml
. one mole of any gas at STP occupies 22.4lt
22400ml of O2 contains 6.023×10^23 molecules.
1ml of O2= 6.023×10^23/22400
Now,
800ml contains = ( 6.023×10^23)×800
=> 2.15×10^22 molecules
therefore, molecules present in one litre air containing 80% volume of O2 at STP is 2.15×10^22 molecules

Answer 2

Answer:

Answer: 2.15x 10^22 molecules.

Explanation:

▪️ Correct question should be: how many molecules of oxygen are present in 1 litre of air containing 80% of O2.

First, we will have to find amount of energy in one oxygen.

Therefore,

➡️ Amount of oxygen present in 1 litre air is = 80% *1000 ml

➡️ (80/100)*1000

=800ml

▪️ We know that, 1 mole of STp occupies 22.4 litre

It is equal to = 22400ml of O2 gas contains 6.022x 10^23 molecules

So,

➡️ 1ml of O2 gas Contains =6.022x10^23/22400

According to question, we have to find 800ml molecules.

Therefore,

800ml contains =(6.022x 10^23/22400) *800

=> 2.15 x 10^22

▪️ Hence, molecules present in 1 litre air containing 80% volume of at STP is 2.15x 10^22 molecules.