Determine the number of moles and and the mass of the sample gas of argon occupying 37.8LatSTP

Answer 1

Use PV = nRT. Substitute P, V, R, T and calculate n = number of moles. Then grams = mols x molar mass = ? Post your work if you get stuck.
Another way is
n = L/22.4
Then grams = n x molar mass