we can use the ideal gas law equation to find the number of moles in the sample.
PV = nRT
where P - pressure 1 atm x 101 325 Pa/atm = 101 325 Pa
V - volume - 2.05 x 10⁻³ m³
n - number of moles
R - universal gas constant - 8.314 Jmol⁻¹K⁻¹
T - temperature - 309 K
101 325 Pa x 2.05 x 10⁻³ m³ = n x 8.314 Jmol⁻¹K⁻¹ x 309 K
n = 0.081 mol
answer is 0.081 mol
