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

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

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.

EASY

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Statement = The numerical value of "a" for $H_{2} O$ is higher than $C_{6} H_{6} .$ Explanation = $H_{2} O$ possesses H - bonding.

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Important Questions on States of Matter: Gases and Liquids

HARD

Chemistry>Physical Chemistry>States of Matter: Gases and Liquids>Van Der Waals Equation

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: Gases and Liquids>Van Der Waals Equation

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: Gases and Liquids>Van Der Waals Equation

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

MEDIUM

Chemistry>Physical Chemistry>States of Matter: Gases and Liquids>Van Der Waals Equation

Which equation will explain the nature of

PV

versus

P

curve for

{CO}_{2}

gas at moderately low pressure?

EASY

Chemistry>Physical Chemistry>States of Matter: Gases and Liquids>Van Der Waals Equation

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 ?

EASY

Chemistry>Physical Chemistry>States of Matter: Gases and Liquids>Van Der Waals Equation

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

EASY

Chemistry>Physical Chemistry>States of Matter: Gases and Liquids>Van Der Waals Equation

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

HARD

Chemistry>Physical Chemistry>States of Matter: Gases and Liquids>Van Der Waals Equation

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

EASY

Chemistry>Physical Chemistry>States of Matter: Gases and Liquids>Van Der Waals Equation

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:

HARD

Chemistry>Physical Chemistry>States of Matter: Gases and Liquids>Van Der Waals Equation

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>Van Der Waals Equation

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: Gases and Liquids>Van Der Waals Equation

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

MEDIUM

Chemistry>Physical Chemistry>States of Matter: Gases and Liquids>Van Der Waals Equation

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: Gases and Liquids>Van Der Waals Equation

Which of the following represents Van der Waals equation for

n

moles of the gas?

EASY

Chemistry>Physical Chemistry>States of Matter: Gases and Liquids>Van Der Waals Equation

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

HARD

Chemistry>Physical Chemistry>States of Matter: Gases and Liquids>Van Der Waals Equation

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]

MEDIUM

Chemistry>Physical Chemistry>States of Matter: Gases and Liquids>Van Der Waals Equation

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)

MEDIUM

Chemistry>Physical Chemistry>States of Matter: Gases and Liquids>Van Der Waals Equation

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

EASY

Chemistry>Physical Chemistry>States of Matter: Gases and Liquids>Van Der Waals Equation

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>Van Der Waals Equation

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,

Statement = The numerical value of "a" for H2O is higher than C6H6. Explanation = H2O possesses H - bonding.

Important Questions on States of Matter: Gases and Liquids

Learn and Prepare for any exam you want !

Statement = The numerical value of "a" for $H_{2} O$ is higher than $C_{6} H_{6} .$ Explanation = $H_{2} O$ possesses H - bonding.