Question

What is the mass (in grams) of 23.00 L of propane vapor (C₃H₈) at STP?

Answer 1

• At STP 22.4L of any gas contains 1mol of gas
• 1L contains=0.04mol
• 23L contains=0.04(23)=0.92mol

Now

Molar mass of Propane:-

• 3(12)+8(1)=44g/mol

$\\ \tt\hookrightarrow No\:of\:moles=\dfrac{Given\:mass}{Molar\:mass}$

$\\ \tt\hookrightarrow Given\:mass=No\:of\:moles\times Molar\:mass{}$

$\\ \tt\hookrightarrow Given\:mass=0.92(44)$

$\\ \tt\hookrightarrow Given\:mass=40.48g$