The same number of nitrogen molecules as in 25.00 g of Oxygen?

Answer 1

Since Avogadro's number represents a specific number of particles (atoms, molecules, ions, electrons, etc), if the number of molecules of two substances is the same, their number of moles will also be same.

Molar mass of O2 = 2 x 16.00 = 32.00 g / mol
Mole of O2 = 25.00 g / 32.00 g/mol = 0.78125 mol

Therefore, the mole of N2 = 0.78125 mol
Molar mass of N2 = 2 x 14.01 = 28.02 g/mol
Mass of N2 = 0.78125 mol x 28.02 g/mol = 21.89 g

Answer 2

25 g of oxygen is 25/32 moles (appx 0.77)
So molecules in 0.77 moles=0.77*6.02x10^23=
4.6x10^23 appx.