What is the density of PF3 at STP ??????

[Toothguy80]

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This is my way:

Density = mass / volume

Mass = P + 3F = 87.97
Volume = 22.4 L because it says at STP, right?

When you divide them, you get 3.93 but the answer in Top Score is 3.22. They gave (R = 0.1 atmL/molK) but i didnt bother using this cuz I thought we didn't need to.

Why?

 

[bryanttttttta]

In this problem, they rounded R= .08201 to just .1 This changes the the end result.

When you see something unfamiliar like R= .1 go back to basics with equations

PV=nRT ideal gas law

d=PM/RT where M is molar mass, R is gas constant

d = [(1atm)(87.97 g/mol)]/[(.1 atmL/molK)(273K)]
d = 3.22 g/L


🙂 Man, this brings back gooodd times. haha

 

[Toothguy80]

Great, thanks