A container has a volume of 15 L15L and holds 9 mol9mol of gas. If the container is compressed such that its new volume is 8 L8L, how many moles of gas must be released from the container to maintain a constant temperature and pressure?

1 Answer
Sep 1, 2017

See below

Explanation:

v= 15Lv=15L
n = 9n=9

According to Ideal Gas equation

PV = nRT-----------(I)PV=nRT(I)

Where
RR is a constant whose value depends
PP is pressure
VV is volume
nn is moles
TT is temperature

P15 = 9TRP15=9TR

Now moving on to the second condition

v = 8Lv=8L
n = ?n=?

PV = nRTPV=nRT

P8 = nRT --------- (II)P8=nRT(II)

Dividing (I) and (II)

We have,

(P15)/(P8) = (9RT)/(nRT)P15P8=9RTnRT

Since the given conditions are same for both the cases, These can be canceled out..... So we are left with

(15)/(8) = (9)/(n)158=9n

72/15 = n7215=n

n = 4.8n=4.8

Therefore 9 - 4.8 moles need to be removed

i.e 4.2 mol4.2mol to maintain the same pressure and temperature.