Consider the following table: Gas a / k P a d m 6 m o l - 1 b / d m 3 m o l - 1 A 642.32 0.05196 B 155.21 0.04136 C 431.91 0.05196 D 155.21 0.4382 a and b are vander Waals constants. The correct statement about the gases is:

Gas C will occupy more volume than gas A ; gas B will be more compressible than gas D

Gas C will occupy more volume than gas A ; gas B will be lesser compressible than gas D

Gas C will occupy lesser volume than gas A ; gas B will be lesser compressible than gas D

Gas C will occupy lesser volume than gas A ; gas B will be more compressible than gas D

Van der Waal's equation for a gas is stated as, P = nRT V - nb - a n V 2 . This equation reduces to the perfect gas equation, P = nRT V When,

temperature is sufficiently high and pressure is low.

both temperature and pressure are very low.

both temperature and pressure are very high.

temperature is sufficiently low and pressure is high.

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Positive deviation from ideal behaviour takes place because of

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Important Questions on States of Matter

EASY

Chemistry>Physical Chemistry>States of Matter>Behaviour of Real Gases

For a van der Waals' gas, the term $(\frac{ab}{V^{2}})$ represents some

MEDIUM

Chemistry>Physical Chemistry>States of Matter>Behaviour of Real Gases

The van der Waals constant

' a'

is the measure of intermolecular force of attraction in a gas. The correct decreasing order of

' a'

for the given set of molecules is

EASY

Chemistry>Physical Chemistry>States of Matter>Behaviour of Real Gases

Which of the following represents Van der Waals equation for

n

moles of the gas?

MEDIUM

Chemistry>Physical Chemistry>States of Matter>Behaviour of Real Gases

Which among the following statements is/are incorrect regarding real gases?
(i) Their compressibility factor is never equal to unity

(Z \neq 1)

.
(ii) The deviations from ideal behavior are less at low pressures and high temperatures.
(iii) Intermolecular forces among gas molecules are equal to zero.
(iv) The obey Van der Waals equation,

PV = nRT

EASY

Chemistry>Physical Chemistry>States of Matter>Behaviour of Real Gases

Consider the following table:

Gas	$a / (k P a d m^{6} m o l^{- 1})$	$b / (d m^{3} m o l^{- 1})$
A	$642.32$	$0.05196$
B	$155.21$	$0.04136$
C	$431.91$	$0.05196$
D	$155.21$	$0.4382$

a

and

b

are vander Waals constants. The correct statement about the gases is:

EASY

Chemistry>Physical Chemistry>States of Matter>Behaviour of Real Gases

The unit of the van der Waals gas equation parameter $' a'$ in $(P + \frac{{an}^{2}}{V^{2}}) (V - nb) = nRT$ is:

HARD

Chemistry>Physical Chemistry>States of Matter>Behaviour of Real Gases

Suppose that,

300 gm

C_{2} H_{6} (g)

is confined in a

5 L

container at

27^{o} C

. Calculate the pressure exerted by ethane from van der Waals equation of state?

a = 5.0 d m^{6} atm {mol}^{- 2}, b = 0.09 {dm}^{3} {mol}^{- 1}

HARD

Chemistry>Physical Chemistry>States of Matter>Behaviour of Real Gases

For $1 mol$ of gas, the plot of $pV$ vs $p$ is shown below. p is the pressure and $V$ is the volume of the gas.

Question Image

What is the value of compressibility factor at point $A$ ?

MEDIUM

Chemistry>Physical Chemistry>States of Matter>Behaviour of Real Gases

At low pressure, the Van der Waals equation is reduced to:

HARD

Chemistry>Physical Chemistry>States of Matter>Behaviour of Real Gases

Four gases

P, Q, R

and

S

have almost same values of

b

but their

a

values

(a & b

are van der Waal s' constant) are in the order

Q < R < S < P

. At a particular temperature, among the four gases, the most easily liquifiable one is

MEDIUM

Chemistry>Physical Chemistry>States of Matter>Behaviour of Real Gases

Which of the following options correctly represents the relations of compressibility factor (z) and van der Waals equation for

1

mole of gas at low pressure?

EASY

Chemistry>Physical Chemistry>States of Matter>Behaviour of Real Gases

At very high pressures, the compressibility factor of one mole of a gas is given by:

EASY

Chemistry>Physical Chemistry>States of Matter>Behaviour of Real Gases

The correction factor 'a' to the ideal gas equation corresponds to which of the following?

MEDIUM

Chemistry>Physical Chemistry>States of Matter>Behaviour of Real Gases

Which equation will explain the nature of

PV

versus

P

curve for

{CO}_{2}

gas at moderately low pressure?

HARD

Chemistry>Physical Chemistry>States of Matter>Behaviour of Real Gases

For a real gas at

25 ° C

temperature and high pressure (

99

bar) the value of compressibility factor is

2

, so the value of Van der Waal's constant '

b

' should be_____

\times 10^{- 2} L {mol}^{- 1}

(Given

R = 0.083 L

bar

K^{- 1} {mol}^{- 1}

)

HARD

Chemistry>Physical Chemistry>States of Matter>Behaviour of Real Gases

In thermodynamics, the $P - V$ work done is given by $w = - \int {dVP}_{ext}$ . For a system undergoing a particular process, the work done is,

$w = - \int dV (\frac{RT}{V - b} - \frac{a}{V^{2}})$ . This equation is applicable to a

HARD

Chemistry>Physical Chemistry>States of Matter>Behaviour of Real Gases

One mole of a monoatomic real gas satisfied the equation

p (V - b) = R T

where b is a constant. The relationship of interatomic potential V(r) and interatomic distance r for the gas is given by

EASY

Chemistry>Physical Chemistry>States of Matter>Behaviour of Real Gases

The maximum deviation from ideal gas behaviour among the following is expected from

EASY

Chemistry>Physical Chemistry>States of Matter>Behaviour of Real Gases

At a given temperature

T,

gases

N e, A r, X e

and

K r

are found to deviate from ideal gas behaviour. Their equation of state is given as

p = \frac{R T}{V - b}

T .

Here,

b

is the van der Waals constant. Which gas will exhibit steepest increase in the plot of

Z

(compression factor) vs

p ?

HARD

Chemistry>Physical Chemistry>States of Matter>Behaviour of Real Gases

Van der Waal's equation for a gas is stated as,

P = \frac{nRT}{V - nb} - a {(\frac{n}{V})}^{2}

.

This equation reduces to the perfect gas equation,

P = \frac{nRT}{V}

When,

Positive deviation from ideal behaviour takes place because of

Important Questions on States of Matter

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