A sample of neon has a volume of 75.8 L at STP. Calculate the number of moles

3.38 moles of neon

Explanation:

First you have to multiply the volume (75.8 L) by the density to get the mass. Neon has a density of 0.9002 g/L at STP, we can just assume it's 0.9 g/L.

That leaves the mass at 68.22 g

Then, you divide the mass by the molar mass to get the number of moles. The molar mass of neon is 20.1797 u, we can leave it at 20.18

That leaves you at approximately 3.38 moles of neon