Question
consider 2 sample of nitrogen gas. sample 1 contains 1.5 mol of N2 and has a volume of 36.7L at 25C and 1 atm. sample 2 has a volume of 16.5L at 25C and 1 atm. calculate the number of moles of N2 in sample 2
do i use the pv= nrt equation? and do i only use the information given for sample 2 since you are finding moles in sample 2?
so you can ignore the info. for sample 1?
do i use the pv= nrt equation? and do i only use the information given for sample 2 since you are finding moles in sample 2?
so you can ignore the info. for sample 1?
Answers
DrBob222
You can do this two ways.
One way is to use PV = nRT and, as you say, ignore sample 1.
(1 atm)(16.7 L) = n*0.08206*298 and solve for n, number of moles.
OR you can forget the PV = nRT and use the information from the two gases. I suspect the problem is trying to illustrate Avogadro's Law that equal volumes of gases at the same P and T contain equal number of molecules.
So if 1.5 mol are in the 36.7 L sample and we want to know moles in the 16.5 L sample, we can use the ratio
1.5 mol x (16.5/36.7) = ??
You should get the same answer either way.
One way is to use PV = nRT and, as you say, ignore sample 1.
(1 atm)(16.7 L) = n*0.08206*298 and solve for n, number of moles.
OR you can forget the PV = nRT and use the information from the two gases. I suspect the problem is trying to illustrate Avogadro's Law that equal volumes of gases at the same P and T contain equal number of molecules.
So if 1.5 mol are in the 36.7 L sample and we want to know moles in the 16.5 L sample, we can use the ratio
1.5 mol x (16.5/36.7) = ??
You should get the same answer either way.