vanderwal ------ damn easy ---

For non-zero value of force of attraction between gas molecules for large volume, gas equation will be ------ ??

my ans is

PV = nRT - n2a/V

(i took b negligible as its large volume.. )

plz verify..

15 Answers

3
msp ·

hey sky the relation PV=nRT because the term n2a/V is a measure of internal pressure for weker force of attraction it can be negligible

1
voldy ·

how can we do that ? nothing is sadi abt the P value no ? if it's low then , the pressure correction is not negligible. ? what do u say?

3
msp ·

srinath it is not mentioned openly.in the question it has given that force of attraction is negligble.This condition is satisfied at high pressure.correct if i wrong.

1357
Manish Shankar ·

In this case you cannot neglect anything as it is in terms of 'n'.

The vaderwaal equation will not be reduced (think if 'n' is large)

1
skygirl ·

bhaiya u mean we have to consider 'b' as well?

but therewas no option containing both 'a' and 'b'..

the options are:

a) PV = nRT - n^2a/V

b) PV = nRT + nbP

c) P= nRT/ V-b

d) PV nRT

3
msp ·

why sir

1
skygirl ·

@SANKARA,
becos if 'n' is large, nb term will become significant...

3
msp ·

sky whats the final ans

3
msp ·

sky can u tell me the reason for considering large value of n dats wat i asked

1
skygirl ·

it may be large , it may be small...

but if we take it large,,, then we cant neglect ne of the VW corrections..

the ans given is PV=nRT

but i dun have ne idea y it shud be this...

3
msp ·

whatever may be the value the pressure correction can be neglected because the molecules should be free in the and the volume correction term can also be neglected for the larger value of volume the pressure correction will be higher if the intermolecular forces are higher.

3
msp ·

one question a gas can be easily liquifieable
if it has higher value of a
has higher value of b
has lower value of a
has lower value of b

1357
Manish Shankar ·

For one mole it will be PV=RT

but I'm not sure for 'n' moles

For one mole as the volume is large 'b' can be neglected.
Also the molecules are far apart in that case, so the force of attraction between them also becomes negligible.

so equation becomes PV=RT

1
skygirl ·

has hihger value of a.

1
gagar.iitk ·

skygirl you are getting the right answer ......b can be neglected but a can't be

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