Moles Problem

Hi, don't quite understand how this works for these questions.

1.How many atoms are in 0.25 moles of O2 at STP.

I got the answer as 0.25 x Av constant which is 1.5x10^23, but the answer is 3.01x10^23 which is half of Av constant not 1/4 which doesnt seem to make much sense to me.

2. How many litres are in 56 grams of N2 at STP.

1 Mole of a gas has 22.4L and here there are 4 moles so won't it be 89.6, but the answer is 44.8L. Once again, don't understand how they got this answer.

Really Appreciate the help!

For question 1:
There are two atoms of oxygen in a molecule.
This means there are 0.5 moles of oxygen atoms.
Hence 0.5*6.02x10^23=3.01x10^23

Hi, sorry didn't quite understand that 0.5 moles part, could you explain that please. Thanks!

For question 2:

If we use Number of moles = mass/molar mass
Molar mass = 14+14
you get 56/24.0 = 2.00 moles

So there are 2 moles.