A piston filled with 0.04 mol of an ideal gas expands reversibly from 50.0 mL to 375 mL at a constant temperature of 3 7 . 0 ∘ C . As it does so, it absorbs 208 J of heat. The values of q and w for the process will be (R = 8.314 J/mol K) (ln7.5 = 2.01)

q = + 2 0 8 J , w ⁡ = - 2 0 8 J

q = + 2 0 8 J , w ⁡ = + 2 0 8 J

q = - 2 0 8 J , w ⁡ = - 2 0 8 J

EASY

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Three closed rigid vessels, A, B and C without energy transfer with surroundings, which initially contain three different gases at different temperatures are connected by tube of negligible volume. The vessel A contains $2 moles Ne$ gas, at $300 K$ , vessel 'B' contains $2 moles {SO}_{2}$ gas at $400 K$ and vessel 'C' contains $3 moles {CO}_{2}$ gas at temperature $500 K$ . What is the final pressure (in atm) attained by gases when all valves of connecting three vessels are opened and additional $15.6 kcal$ heat supplied to vessel through valve. The volume of A, B and C vessel is $2, 2 and 3 litre$ respectively.

Given : $R = 2 calorie / mol - K; C_{v} (Ne) = \frac{3}{2} R, Cv (CO) = \frac{5}{2} R and Cv (CO 2) = 3 R$

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Important Questions on Thermodynamics

EASY

Chemistry>Physical Chemistry>Thermodynamics>First Law of Thermodynamics

A system does

200 J

of work and at the same time absorbs

150 J

of heat. The magnitude of the change in internal energy is ______

J

. (Nearest integer)

EASY

Chemistry>Physical Chemistry>Thermodynamics>First Law of Thermodynamics

Which of the following can be considered as the definition/principle of energy?

MEDIUM

Chemistry>Physical Chemistry>Thermodynamics>First Law of Thermodynamics

365

calorie heat is required to evaporate one gram water at

100 {}^{\circ}C

. If the work done by the system is

651.3

calorie, then the increase in internal energy per mole of water will be

MEDIUM

Chemistry>Physical Chemistry>Thermodynamics>First Law of Thermodynamics

A piston filled with 0.04 mol of an ideal gas expands reversibly from 50.0 mL to 375 mL at a constant temperature of

37 . 0^{\circ} C

. As it does so, it absorbs 208 J of heat. The values of q and w for the process will be
(R = 8.314 J/mol K) (ln7.5 = 2.01)

EASY

Chemistry>Physical Chemistry>Thermodynamics>First Law of Thermodynamics

A gas undergoes change from state

A

to state

B

. In this process, the heat absorbed and work done by the gas is

5 J and 8 J

, respectively. Now gas is brought back to

A

by another process during which

3 J

of heat is evolved. In this reverse process of

B to A

MEDIUM

Chemistry>Physical Chemistry>Thermodynamics>First Law of Thermodynamics

A system undergoes a process in which

ΔU = + 300 J

while absorbing

400 J

of heat energy and undergoing an expansion against

0.5

bar. What is the change in volume (in

L) ?

HARD

Chemistry>Physical Chemistry>Thermodynamics>First Law of Thermodynamics

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 $= 4.2 J g^{- 1} K^{- 1}$ ]

EASY

Chemistry>Physical Chemistry>Thermodynamics>First Law of Thermodynamics

If work done by the system is

300

Joule when

100

Cal, heat is supplied to it. The change in internal energy during the process is :-

MEDIUM

Chemistry>Physical Chemistry>Thermodynamics>First Law of Thermodynamics

The molar enthalpy change for

H_{2} O (l) ⇌ H_{2} O (g)

373 K

and

1 atm

40 kJ / mol

. Assuming ideal behaviour, the internal energy change for vaporization of

1 mol

of water at

373 K

and

1 atm

kJ {mol}^{- 1}

is:

EASY

Chemistry>Physical Chemistry>Thermodynamics>First Law of Thermodynamics

Following figure shows two processes

A

and

B

for a gas. If

∆ Q_{A}

and

∆ Q_{B}

are the amount of heat absorbed by the system in two cases, and

∆ U_{A}

and

∆ U_{B}

are changes in internal energies, respectively, then:
Question Image

MEDIUM

Chemistry>Physical Chemistry>Thermodynamics>First Law of Thermodynamics

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

5

atm, from an initial value of

10 L

to a final volume of

15 L,

find the change in the internal energy

(ΔU)

of the gas.

EASY

Chemistry>Physical Chemistry>Thermodynamics>First Law of Thermodynamics

Δ U

is equal to:

MEDIUM

Chemistry>Physical Chemistry>Thermodynamics>First Law of Thermodynamics

A system absorbs

6 kJ

of heat and does

1.5 kJ

of work on its surroundings. The change in internal energy is _____.

EASY

Chemistry>Physical Chemistry>Thermodynamics>First Law of Thermodynamics

When the temperature of

2

moles of an ideal gas is increased by

20 ° C

at constant pressure, find the work involved in the process.

MEDIUM

Chemistry>Physical Chemistry>Thermodynamics>First Law of Thermodynamics

A system gives out

30 J

of heat and does

75 J

of work. What is the internal energy change?

MEDIUM

Chemistry>Physical Chemistry>Thermodynamics>First Law of Thermodynamics

$2.2 g$ of nitrous oxide $(N_{2} O)$ gas is cooled at a constant pressure of $1$ atm from $310 K$ to $270 K$ causing the compression of the gas from $217.1 mL$ to $167.75 mL$ . The change in internal energy of the process, $△ U$ is $' - x' J$ . The value of $' x'$ is _____.

[nearest integer]

(Given: atomic mass of $N = 14 g {mol}^{- 1}$ and of $O = 16 g {mol}^{- 1}$ . Molar heat capacity of $N_{2} O$ is $100 {JK}^{- 1} {mol}^{- 1}$ )

EASY

Chemistry>Physical Chemistry>Thermodynamics>First Law of Thermodynamics

Which of the following equations represents the first law of thermodynamics under isobaric conditions?

EASY

Chemistry>Physical Chemistry>Thermodynamics>First Law of Thermodynamics

During compression of a spring the work done is

10 k J

and

2 k J

escaped to the surroundings as heat. The change in internal energy,

Δ U (i n k J)

is:

EASY

Chemistry>Physical Chemistry>Thermodynamics>First Law of Thermodynamics

The first law of thermodynamics for isothermal process is

HARD

Chemistry>Physical Chemistry>Thermodynamics>First Law of Thermodynamics

The above

P - V

diagram represents the thermodynamic cycle of an engine, operating with an ideal mono-atomic gas. The amount of heat, extracted from the source in a single cycle, is:

Important Questions on Thermodynamics

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