Mass NF₃ at STP : 50.06 g
Further explanation
Conditions at T 0 ° C and P 1 atm are stated by STP (Standard Temperature and Pressure). At STP, Vm is 22.4 liters/mol.
15.8 L at STP, mol NF₃ :
[tex]\tt \dfrac{15.8}{22.4}=0.705[/tex]
mass NF₃ (MW=71 g/mol) :
[tex]\tt mass=mol\times MW\\\\mass=0.705\times 71\\\\mass=50.06~g[/tex]
