Answer:
530 g
Explanation:
Ideal gas law:
PV = nRT
(4.0×10⁵ Pa) (0.20 m³) = n (8.31 Pa m³ /mol /K) (20+273.15 K)
n = 32.8 mol
Find the mass using the molar mass:
32.8 mol × (16 g / mol) = 525 g
Rounded to two significant figures, the mass is 530 g.
Note: I used the molar mass provided, but oxygen is usually in a diatomic state (O₂), which would make the molar mass 32 g/mol.