What are the number of moles?

Question

A 319 mL container holds 0.146 g of Ne and an unknown amount of Ar at 35°C and a total pressure of 637 mmHg. Calculate the moles of Ar present.

Answer 1

First, convert the 0.146 g of Neon to moles.
Since the ideal gas law only concerns moles, irregardless of what the gases are,
PV=nRT.
So sub in your pressure and volume and temp, and solve for n, which will be larger than the moles of Neon. The difference is the moles of Argon.