Calculate the Molecular Weight (MW) of a hydrocarbon as if 0.5813 g of this gas completely fills a 250.0 mL flask at a temperature of 24.4 C and pressure of 742.6 mmHg. Show all work and assume ideal behavior.

Answer 1

Use PV = nRT, solve for n, then n = grams/molar mass. Solve for molar mass(molecular weight).
Remember P must be in atmospheres, V in liters, and T in kelvin.

Answer 2

what does the R stand for again? the grams?

Answer 3

In the units I quoted R =- 0.08206 L*atm/mol*K.