Question

calculate number of molecules of oxygen in 6.4g of oxygen?

Answer 1

Mass of oxygen = 6.4g

Molecular mass of oxygen = 32g

Number of moles = mass / molecular mass = 6.4 / 32 = 0.2 moles

Number of molecules = Avogadro number X number of moles

= 6.023 X 10²³ X 0.2 = 4.80 X 10²³ molecules

So 6.4g of oxygen contains 4.80 X 10²³ molecules.