Answer:
0.0401 (3 s.f.)
Step-by-step explanation:
Assuming that the gas is a perfect gas and obeys the ideal gas law,
pV = nRT.
In the above gas law, p stands for pressure, V stands for volume, n stands for the number of moles and T stands for pressure. I will use the R (universal gas constant) value of 0.08206 L·atm/K·mol in the working below.
At Standard Temperature and Pressure (STP), the pressure is at 1 atm and the temperature is at 273.15 K.
pV = nRT
Substitute p= 1 atm, V= 0.5 L, T= 273.15,
1(0.5)= n(0.08206)(273.15)
Solve for n:
n= 44.829378
Number of moles× mw= mass
∴ mw= mass ÷ number of moles
Given that the mass is 1.80 g,
Molar mass of gas
= 1.80 ÷44.829378
= 0.0401 (3 s.f.)