calculate the number of moles , molecules and atoms present in 11.2 liters of H2 at STP

1 mole of a gas has 22.4 L of volume at STP.

Therefore, 11.2 L of hydrogen gas at STP has 11.2 / 22.4 = 0.5 mol

1 mole of H₂ has 6.022 x 10²³ molecules

Therefore, 0.5 mol of H₂ has 0.5 x 6.022 x 10²³ = 3.011 x 10²³ molecules.

Now, 1 molecule of H₂ has 2 atoms of H

Therefore, 3.011 x 10²³ molecules of H₂ has 2 x 3.011 x 10²³ = 6.022 x 10²³ atoms of H

Hence, the number of moles, molecules and atoms present in 11.2 liters of H₂ at STP are 0.5 , 3.011 x 10²³ and 6.022 x 10²³ respectively.