Answer:
1.86 moles
Step-by-step explanation:
The equation you need to use is PV = nRT, where n is the value you are searching for.
P = 100.0 kPA
V = 50.0 dm^3
n = ?
R = 8.314
T = 50 celsius converted to kelvin (323 k)
Multiply the pressure times the volume (100*50) and divide it by the constant (R) by the temperature (8.314*323).
(100*50) / (8.314*323) = 5000 / 2685.422 = 1.86 moles