Topscore Gen. Chem #56

[jdpaul14]

Advertisement - Members don't see this ad

Hey Guys,

Does anyone know how to do question #56 on the 2nd Exam in Topscore?

What is the density of ammonia gas at 2.00 atm pressure and 25 degrees Celsius (R = 0.1atm L/mol K)?


I don't get what formula they used and their solution isn't making any sense to me....please help!

 

[Blarelli]

Hey Guys,

Does anyone know how to do question #56 on the 2nd Exam in Topscore?

What is the density of ammonia gas at 2.00 atm pressure and 25 degrees Celsius (R = 0.1atm L/mol K)?


I don't get what formula they used and their solution isn't making any sense to me....please help!

I might be wrong, but I think they are using PV=nRT. Assume 1 liter of volume, and solve for n using n=PV/RT.

n=(2.00atm x 1.00 L)/((0.1 atm L/mol K)(298 K))=0.0671 mol NH3.

0.0671 moles of NH3 x the molar mass 17.03 g/mol = 1.14 g/L. If needed, convert into g/mL.

I think everything is correct, but maybe not.

 

[sweetcinuhstix]

Density of a gas is related to molar mass of gas.

Density of gas=(Pressure X Molar Mass)/ (R X T)
Density of gas=(2 X 17)/ (.0821/(25+273))
Density of gas=1.42

I think this should be right. Please tell me if I am wrong.