Answer:
.7689 mol
15.516 g
Explanation:
Use the Ideal Gas Law, PV = nRT.
Make sure to use the correct ideal gas constant R. You can either put R in torr, or you can change the pressure to atm. I've just used the torr ideal gas constant.
481.1 torr * 29.9 L = n 62.364 LTorr/molK * 300 K
14384.89 = 18709.2n
n = .7689 mol
The molar mass of neon (remember that neon gas = Ne, it's not diatomic) is 20.18 g/mol from the periodic table.
.7689 mol * 20.18 g/mol = 15.516 g