At STP, a flask contains 755 grams of ammonia. What is the volume of the flask?

Answer 1

755 g NH₃ x (1 mol NH₃ / 17.03 g NH₃) = 44.3 mol NH₃

At STP, 1 mole of a gas occupies a volume of 22.4 L. Setup a proportion to determine the volume of NH₃ in the flask, which = volume of the flask as well.

1 mol = 22.4 L

44.3 mol = ? L

? = (44.3 mol x 22.4 L / 1 mol) = 992 L (to 3 significant figures)

Answer 2

If we know we're at STP (standard temperature and pressure), then our temperature is 273.15 K, and our pressure is 1 atm. Therefore, we can find the volume of the flask using the Ideal Gas Law:

PV = nRT

Solving for V:

V = nRT/P

V = (755 g NH₃ x (1 mol NH₃/17.031 g NH₃))*(0.0821 L*atm/mol*K)*(273.15 K)/(1 atm)

V = 995.15 L