Question

Helium gas occupies a volume of 0.03 at a pressure of 2×10 pa (NM) and temperature of 300.calculates the mass of helium

Answer 1

300 what? 0.03 what?

I will assume 300 K and 0.03 L.
PV = nRT
P = 20 pa/1000 = 0.020 kPa
V = 0.03 L
n = ?
R = 8.314
T = 300
Solve n = moles.Then
n = moles = g/molar mass.
You know moles and you know molar mass. Solve for grams.