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.

For one mole of a van der Waals' gas, the compressibility factor Z = p V R T at a fixed volume will certainly decrease, if [Given : " a " and " b " are standard parameters for van der Waals' gas]

" b " decreases and " a " increases at constant temperature

" b " increases and " a " decreases at constant temperature

temperature increases at constant a n and " b " values

" b " increases at constant " a " and temperature

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Positive deviation from ideal behaviour takes place because of

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Important Questions on States of Matter: Gases and Liquids

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Chemistry>Physical Chemistry>States of Matter: Gases and Liquids>Real Gas

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,

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Chemistry>Physical Chemistry>States of Matter: Gases and Liquids>Real Gas

A gas at

350 K

and

15

bar has a molar volume

20

per cent smaller than that for an ideal gas under the same conditions. The correct option about the gas, and its compressibility factor

(Z)

EASY

Chemistry>Physical Chemistry>States of Matter: Gases and Liquids>Real Gas

For an ideal gas, the compressibility factor is

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Chemistry>Physical Chemistry>States of Matter: Gases and Liquids>Real Gas

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 ?

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Chemistry>Physical Chemistry>States of Matter: Gases and Liquids>Real Gas

A gas such as carbon monoxide would be most likely to obey the ideal gas law at:

EASY

Chemistry>Physical Chemistry>States of Matter: Gases and Liquids>Real Gas

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

HARD

Chemistry>Physical Chemistry>States of Matter: Gases and Liquids>Real Gas

For one mole of a van der Waals' gas, the compressibility factor

Z = (\frac{p V}{R T})

at a fixed volume will certainly decrease, if
[Given : " a " and " b " are standard parameters for van der Waals' gas]

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Chemistry>Physical Chemistry>States of Matter: Gases and Liquids>Real Gas

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

HARD

Chemistry>Physical Chemistry>States of Matter: Gases and Liquids>Real Gas

Which one of the following plots is correct for the behaviour of ideal and real gases?

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Chemistry>Physical Chemistry>States of Matter: Gases and Liquids>Real Gas

The pressure

(p)

and volume

(V)

isotherm of a van der Waals' gas, at the temperature at which it undergoes gas to liquid transition, is correctly represented by

HARD

Chemistry>Physical Chemistry>States of Matter: Gases and Liquids>Real Gas

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

EASY

Chemistry>Physical Chemistry>States of Matter: Gases and Liquids>Real Gas

Among the following, the incorrect statement is:

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Chemistry>Physical Chemistry>States of Matter: Gases and Liquids>Real Gas

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

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Chemistry>Physical Chemistry>States of Matter: Gases and Liquids>Real Gas

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

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Chemistry>Physical Chemistry>States of Matter: Gases and Liquids>Real Gas

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

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Chemistry>Physical Chemistry>States of Matter: Gases and Liquids>Real Gas

Which of the following represents Van der Waals equation for

n

moles of the gas?

HARD

Chemistry>Physical Chemistry>States of Matter: Gases and Liquids>Real Gas

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}

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Chemistry>Physical Chemistry>States of Matter: Gases and Liquids>Real Gas

If Z is the compressibility factor, then Van der Waal's equation at low pressure can be written as:

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Chemistry>Physical Chemistry>States of Matter: Gases and Liquids>Real Gas

The variation of the compressibility factor $(Z)$ with pressure $(P in bar)$ for some gases, are shown in the figure below. Identify the gases $(A), (B)$ and $(C)$ .

Question Image

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Chemistry>Physical Chemistry>States of Matter: Gases and Liquids>Real Gas

When does a gas deviate the most from its ideal behavior?

Positive deviation from ideal behaviour takes place because of

Important Questions on States of Matter: Gases and Liquids

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