List of top Chemistry Questions on Thermodynamics

Identify the correct statements from the following:

• Bomb calorimeter is used to determine the heat absorbed by water in a chemical reaction at constant volume

• Heat capacity is an extensive property

• The units of entropy are \(J\,K^{-1}\)
The correct answer is

At T(K) in a reaction \(A(g) \rightarrow B(g) + C(g)\), x J of heat was absorbed and y J of work is done by the system. What is \(\Delta_r H\) (in J) for the reaction? (R= gas constant)

At constant temperature, one mole of an ideal gas of volume 2L expanded to 100 L against an external pressure of 1 atm under reversible conditions. What is the work done (in J)? (1 L atm = 101.3 J; \(\log 5 = 0.7\))

At constant temperature, one mole of an ideal gas of volume 2L was expanded to 100 L against an external pressure of 1 atm under reversible conditions. What is the change in internal energy? \((1 L atm=101.3~J; log~5=0.7)\)

What is the work done (in J $mol^{-1}$) to vaporise 1 mole of $H_2O(l)$ to $H_2O(g)$ at 1 bar pressure and $100^{\circ}C$? ($\Delta_{vap}H = 41$ kJ $mol^{-1}$; $\Delta U = 37.9$ kJ $mol^{-1}$)

Consider the following data for the reaction
$X_2(g) + Y_2(g) \rightleftharpoons 2XY(g)$
at 600 K. The $\Delta_r G^\ominus$ (in kJ $\text{mol}^{-1}$) for the reaction is :}

Match List-I with List-II.

Choose the correct answer.

List-I contains various physical/chemical processes, and List-II contains combinations of changes in enthalpy \((\Delta H)\) and entropy \((\Delta S)\). Match each entry in List-I to the appropriate entry in List-II and choose the correct option.

An ideal gas expands from volume $V_{1}$ to $V_{2}$ through an isothermal reversible process. The work done by the system is given by

For a spontaneous process at constant temperature and pressure, the change in Gibbs free energy ($\Delta G$) is

The signs of $\Delta H$ and $\Delta S$ for a reaction to be spontaneous at all temperatures respectively are

At 273 K the maximum work done when pressure on 10g of hydrogen is reduced from 10atm to 1 atm under isothermal reversible conditions is

For which of the following process entropy change ($\Delta S$) is negative ?
I) Sublimation of dry ice
II) Freezing of water
III) Crystallisation of the dissolved substance
IV) Burning of rocket fuel

The number of extensive and intensive properties in the list given below is respectively:
Density, enthalpy, mass, temperature, volume, pressure

The signs of $\Delta$H and $\Delta$s for a reaction to be spontaneous at all temperatures respectively are

For which of the following process entropy change ($\Delta$S) is negative ?
• [I)] Sublimation of dry ice
• [II)] Freezing of water
• [III)] Crystallisation of the dissolved substance
• [IV)] Burning of rocket fuel

At 273 K the maximum work done when pressure on 10g of hydrogen is reduced from 10atm to 1 atm under isothermal, reversible conditions is

Calculate the work done in oxidation of 2 moles of \(SO_2\) at 298 K, if \(SO_{2(g) + \frac{1}{2}O_{2(g)} \rightarrow SO_{3(g)}\) [Given : R = 8.314 J/K/mol].}

Which of the following statements are not correct?
A. For water, magnitude of \(K_b\) is more than the magnitude of \(K_f\).
B. The elevation in boiling point of water when a non-volatile solute is added to it is larger in magnitude than its depression in freezing point.
C. Osmotic pressure measurement is preferred over any other colligative property to determine molar mass of proteins and polymers.
D. The dimerised form of benzoic acid in benzene is C₆H₅-C-OH ⋯ O=C-C₆H₅

An ideal gas is placed in a container at \( (P_1, V_1, T_1) \) and another ideal gas is placed in a different container at \( (P_2, V_2, T_2) \) are mixed at final pressure of \( P \) and final volume of \( V \). Calculate the final temperature.

Statement-1: Heat capacity at constant volume is always greater than heat capacity at constant pressure.
Statement-2: At constant volume as work done is zero, heat given to the chaotic motion is reflected by increase in temperature.

For process \( X \to Y \), work done by the gas is 10 J and heat absorbed in the process is 2 J. For the reverse process, heat evolved is 6 J. Find the work done for the reverse process.

For reaction $A \rightleftharpoons B$, $\Delta G^{\circ} = 105 - 35 \log T$. Find the transition temperature (in $^{\circ} C$) of the above reaction at 1 bar.

For a reversible adiabatic process involving ideal gas if initial pressure and volume are 8 bar and $0.15 \text{ m}^3$ respectively and final pressure is 1 bar. Calculate |work done| (in Kilo Joule) [$C_V = 2R, C_P = 3R$]