What mass of chlorine gas is necessary to synthesize 174 liters of hydrogen chloride at STP?

The mass of chlorine gas is calculated as follows

find the moles HCl, At STP 1moles = 22.4 liters

what about 174 L

moles = 174l x 1mole/22.4L = 7.77 moles

write the equation for reaction

H2 + Cl2 = 2HCl

by

use of mole ratio between cl2 to HCl (1:2) the moles of Cl2 = 7.77/2 = 3.885 moles

mass is therefore = 3.885 mol x 71 gmol = 275.84 grams