The density of an unknown gas is 4.20 grams per liter at 3.00 atmospheres pressure and 127 degrees celsius.
R=0.0821 L atm mole-1 K-1
2007-01-21 13:39:28 · 3 answers · asked by tortuga_gp08 1 in Science & Mathematics ➔ Chemistry
it is a gas laws question
PV=nRT
presssure in atms (volume in liters)= number of moles (R) (temperature)
use this to find number of mols
then you have the the amount of grams given to you in the question per number of moles that you just solved for
so then find number of grams per mol and you are done.
2007-01-21 13:47:20 · answer #1 · answered by applejacks 3 · 0⤊ 0⤋
Density = Mass / Volume = 4.20 grams / L
Assume volume = 1 L
Mass = 4.20 grams
P1 = 3.00 atm
V1 = 1 L [>> 4.20 grams<<]
T1 = 127 C = (273 + 127) K = 400 K
P2 = 1 atm
V2 = ?
T2 = 0 C = 273 K
Gas law
P2 x V2 / T2 = P1 x V1 / T1
Plug-in and solve for V2
V2 = 2.0475 L
2.0475 L of gas at STP weigh 4.20 grams
1 mole = 22.4 L of gas weigh
= 4.20 x 22.4 / 2.0475 = 45.95 grams
Molecular weight of gas = 45.95
2007-01-21 21:58:48 · answer #2 · answered by Sheen 4 · 0⤊ 0⤋
PV = nRT
Solve for n which is the number of gram moles.
Use as a basis a volume of 1 liter.
divide the mass per liter 4.20 by the number of moles "n" and that will be the molecular weight.
2007-01-21 21:47:05 · answer #3 · answered by Roadkill 6 · 0⤊ 0⤋