There are four steps involved in this stoichiometry problem:
Step 1. Write the balanced chemical equation.
M_r:color(white)(mmmmmmm) 36.46Mr:mmmmmmm36.46
color(white)(mmm)"H"_2 + "Cl"_2 → "2HCl"mmmH2+Cl2→2HCl
2. Convert grams of "HCl"HCl to moles of "HCl"HCl
"Moles of HCl" = 292 color(red)(cancel(color(black)("g HCl"))) × ("1 mol HCl")/(36.46 color(red)(cancel(color(black)("g HCl")))) = "8.009 mol HCl"
Step 3. Convert moles of "HCl" to moles of "Cl"_2
"Moles of Cl"_2 = 8.009color(red)(cancel(color(black)("mol HCl"))) × ("1 mol Cl"_2)/(2 color(red)(cancel(color(black)("mol HCl")))) = "4.004 mol Cl"_2
4. Calculate the volume of "Cl"_2
At STP (1 bar and 0 °C), the molar volume of a gas is 22.71 L.
∴ V = 4.004 color(red)(cancel(color(black)("mol"))) × "22.71 L"/(1 color(red)(cancel(color(black)("mol")))) = "90.9 L"
The volume of "Cl"_2 used is 90.9 L.
Here's a useful video on mass-volume conversions.
