The difference between C ¯ p and C ¯ V is C ¯ p and C ¯ V signify molar quantities]

larger in case of gases in comparison to solids and liquids

larger in case of liquids in comparison to gases and solids

larger in case of solids in comparison to gases liquids

equal in solids, liquids and gases

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Equal volumes of monoatomic and diatomic gases are taken at same temperature and pressure. The ratio of adiabatic exponents of the gases will be-

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Important Questions on Chemical thermodynamics and energetics

HARD

Chemistry>Physical Chemistry>Chemical thermodynamics and energetics>Heat Capacity and Latent Heat

A closed tank has two compartments A and B, both filled with oxygen (assumed to be ideal gas). The partition separating the two compartments is fixed and is a perfect heat insulator (Figure

1

). If the old partition is replaced by a new partition which can slide and conduct heat but does not allow the gas to leak across (Figure

2

), the volume (in

m^{3}

) of the compartment A after the system attains equilibrium is

\frac{20}{x} m^{3}

. Write the value of

x

MEDIUM

Chemistry>Physical Chemistry>Chemical thermodynamics and energetics>Heat Capacity and Latent Heat

A piece of metal weighing

100 g

is heated to

80 ° C

and dropped into

1 kg

of cold water in an insulated container at

15 ° C

. If the final temperature of the water in the container is

15.69 ° C

, the specific heat of the metal in

J / g ° C

. is

MEDIUM

Chemistry>Physical Chemistry>Chemical thermodynamics and energetics>Heat Capacity and Latent Heat

When a

60 W

electric heater is immersed in a gas for

100 s

in a constant volume container with adiabatic walls, the temperature of the gas rises by

5 ° C

. The heat capacity of the given gas is

{JK}^{- 1}

(Nearest integer)

MEDIUM

Chemistry>Physical Chemistry>Chemical thermodynamics and energetics>Heat Capacity and Latent Heat

An ideal gas in a thermally insulated vessel at internal pressure =

P_{1}

, volume =

V_{1}

and absolute temperature =

T_{1}

expands irreversibly against zero external pressure, as shown in the diagram. The final internal pressure, volume and absolute temperature of the gas are

P_{2}

V_{2}

and

T_{2}

, respectively. For this expansion,

Question Image

EASY

Chemistry>Physical Chemistry>Chemical thermodynamics and energetics>Heat Capacity and Latent Heat

The quantity of heat (in $J$ ) required to raise the temperature of $1.0 k g$ of ethanol from $293.45 K$ to the boiling point and then change the liquid to vapor at that temperature is closest to [Given, boiling point of ethanol $351.45 K$ . Specific heat capacity of liquid ethanol $2.44 J g^{- 1} K^{- 1}$ . Latent heat of vaporisation of ethanol $855 J g^{- 1}$ ]

MEDIUM

Chemistry>Physical Chemistry>Chemical thermodynamics and energetics>Heat Capacity and Latent Heat

A gas is allowed to expand in a well-insulated container against a constant external pressure of

2.5 atm

from an initial volume of

2.50 L

to a final volume of

4.50 L .

The change in internal energy

ΔU

of the gas in joules will be

HARD

Chemistry>Physical Chemistry>Chemical thermodynamics and energetics>Heat Capacity and Latent Heat

The molar heat capacity for an ideal gas at constant pressure is $20.785 J K^{- 1} {mol}^{- 1}$ . The change in internal energy is $5000 J$ upon heating it from $300 K$ to $500 K$ . The number of moles of the gas at constant volume is____

(Given: $R = 8.314 J K^{- 1} {mol}^{- 1}$ )

EASY

Chemistry>Physical Chemistry>Chemical thermodynamics and energetics>Heat Capacity and Latent Heat

For one mole of an ideal gas, which of these statements must be true?
(a) Internal energy

(U)

and enthalpy

(H)

each depends on temperature.
(b) Compressibility factor

Z

is not equal to 1
(c)

C_{P, m} - C_{V, m} = R

(d)

dU = C_{v} dT

for any process

EASY

Chemistry>Physical Chemistry>Chemical thermodynamics and energetics>Heat Capacity and Latent Heat

The difference between

{\bar{C}}_{p}

and

{\bar{C}}_{V}

[{\bar{C}}_{p}

and

{\bar{C}}_{V}

signify molar quantities]

HARD

Chemistry>Physical Chemistry>Chemical thermodynamics and energetics>Heat Capacity and Latent Heat

The specific heat of a certain substance is $0.86 J g^{- 1} K^{- 1}$ . Assuming ideal solution behavior, the energy required (in $J$ ) to heat $10 g$ of $1$ molal of its aqueous solution from $300 K$ to $310 K$ is closest to :

[Given: molar mass of the substance $= 58 g {mol}^{- 1}$ ; specific heat of water $= 4.2 J g^{- 1} K^{- 1}$ ]

MEDIUM

Chemistry>Physical Chemistry>Chemical thermodynamics and energetics>Heat Capacity and Latent Heat

5

moles of an ideal gas at

100 K

are allowed to undergo reversible compression till its temperature becomes

200 K .

C_{V} = 28 J K^{- 1},

calculate

∆ U

and

∆ p V

for the process.

(R = 8.0 J K^{- 1} m o l^{- 1})

MEDIUM

Chemistry>Physical Chemistry>Chemical thermodynamics and energetics>Heat Capacity and Latent Heat

At constant volume,

4 m o l

of an ideal gas when heated from

300 K

500 K

changes its internal energy by

5000 J .

The molar heat capacity at constant volume is ________

EASY

Chemistry>Physical Chemistry>Chemical thermodynamics and energetics>Heat Capacity and Latent Heat

Among the following, the set of parameters that represents path functions, is:
i)

q + w

ii)

q

iii)

w

iv)

H - T S

MEDIUM

Chemistry>Physical Chemistry>Chemical thermodynamics and energetics>Heat Capacity and Latent Heat

For the isothermal reversible expansion of an ideal gas

EASY

Chemistry>Physical Chemistry>Chemical thermodynamics and energetics>Heat Capacity and Latent Heat

An ideal gas is allowed to expand from

1 L

10 L

against a constant external pressure of

1

bar. The work done in

k J

is:

MEDIUM

Chemistry>Physical Chemistry>Chemical thermodynamics and energetics>Heat Capacity and Latent Heat

The correct option for free expansion of an ideal gas under adiabatic condition is

EASY

Chemistry>Physical Chemistry>Chemical thermodynamics and energetics>Heat Capacity and Latent Heat

Five moles of an ideal gas at

1

bar and

298 K

is expanded into vacuum to double the volume. The work done is :

MEDIUM

Chemistry>Physical Chemistry>Chemical thermodynamics and energetics>Heat Capacity and Latent Heat

$200 mL$ of $0.2 M HCl$ is mixed with $300 mL$ of $0.1 M NaOH .$ The molar heat of neutralization of this reaction is $- 57.1 kJ .$ The increase in temperature in ${}^{\circ}C$ of the system on mixing is $x \times 10^{- 2} .$ The value of $x$ is (Nearest integer)

[Given: Specific heat of water $= 4.18 J g^{- 1} K^{- 1}$

Density of water $= 1.00 g {cm}^{- 3}$ ]

(Assume no volume change on mixing)

MEDIUM

Chemistry>Physical Chemistry>Chemical thermodynamics and energetics>Heat Capacity and Latent Heat

Two moles of helium gas is mixed with three moles of hydrogen molecules (taken to be rigid). What is the molar specific heat of mixture at constant volume?

(R = 8.3 J / m o l K)

MEDIUM

Chemistry>Physical Chemistry>Chemical thermodynamics and energetics>Heat Capacity and Latent Heat

X g

of ice at

0^{o} C

is added to 340g of water at

20^{o} C

. The final temperature of the resultant mixture is

5^{o} C

. The value of

X

(in g) is closest to

[Heat of fusion of ice

= 333 J / g

; Specific heat of water

= 4.184 J / g . K

]

Equal volumes of monoatomic and diatomic gases are taken at same temperature and pressure. The ratio of adiabatic exponents of the gases will be-

Important Questions on Chemical thermodynamics and energetics

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