AIPMT Prelims Physics Thermodynamics Class 11 Questions

The enthalpy of fusion of water is 1.435 kcal/mol. The molar entropy change for the melting of ice at 0°C

In which of the following reactions, standard reaction entropy change (ΔS°) is positive and standard Gibb’s energy change (ΔG°) decreases sharply with increasing temperature?

Standard enthalpy of vaporisation ΔvapH⁰ for water at 100°C is 40.66 kJmol⁻¹. The internal energy of vaporisation of water at 100°C (in kJ mol⁻¹) is

Liquid oxygen at 50 K is heated to 300 K at constant pressure of 1 atm. The rate of heating is constant. Which one of the following graphs represents the variation of temperature with time?

One mole of an ideal gas goes from an initial state A to final state B via two processes: It first undergoes isothermal expansion from volume V to 3V and then its volume is reduced from 3V to V at constant pressure. The correct P⁻V diagram representing the two processes is:

If the radius of a star is R and it acts as a black body, what would be the temperature of the star, in which the rate of energy production is Q?

A thermodynamic system is taken through the cycle ABCD as shown in figure. Heat rejected by the gas during the cycle is

When 1 kg of ice at 0°C melts to water at 0°C, the resulting change in its entropy, taking latent heat of ice to be 80 cal/°C is

During an isothermal expansion, a confined ideal gas does –150 J of work against its surrounding. This implies that

Which of the following is correct option for free expansion of an ideal gas under adiabatic condition?

If the enthalpy change for the transition of liquid water to steam is 30 kJ mol⁻¹ at 27°C, the entropy change for the process would be

Enthalpy change for the reaction, H₂(g) → 2H(g) is −869.6 kJ. The dissociation energy of H−H bond is

The value of ΔH for the reaction X₂(g) + 4Y₂(g) ⇌ 2XY₄(g) is less than zero. Formation of XY₄(g) will be favoured at

A cylindrical metallic rod in thermal contact with two reservoirs of heat at its two ends conducts an amount of heat Q in time t. The metallic rod is melted and the material is formed into a rod of half the radius of the original rod. What is the amount of heat conducted by the new rod, when placed in thermal contact with the two reservoirs in time t?

If ΔU and ΔW represent the increase in internal energy and work done by the system respectively in a thermodynamical process, which of the following is true?

Standard entropies of X₂, Y₂ and XY₃ are 60, 40 and 50 JK⁻¹mol⁻¹ respectively. For the reaction 1/2 X₂ + 3/2 Y₂ → XY₃, ΔH = -30 kJ to be at equilibrium, the temperature should be

Which of the following alkaline earth metal sulphates has hydration enthalpy higher than the lattice enthalpy?

In thermodynamic processes which of the following statements is not true?

The two ends of a rod of length L and a uniform cross-sectional area A are kept at two temperatures $T_1$ and $T_2$ ($T_1 > T_2$). The rate of heat transfer, $\frac{dQ}{dt}$, through the rod in a steady state is given by:

A black body at 227°C radiates heat at the rate of 7 Cals/cm²s. At a temperature of 727°C, the rate of heat radiated in the same units will be:

The internal energy change in a system that has absorbed 2 Kcals of heat and done 500 J of work is:

The values of ΔH and ΔS for the reaction, C(graphite) + CO₂(g) → 2CO(g) are 170 kJ and 170 JK⁻¹, respectively. This reaction will be spontaneous at

An electric kettle takes 4 Å current at 220 V. How much time will it take to boil 1 kg of water from temperature 20°C ? The temperature of boiling water is 100°C.

If Q, E and W denote respectively the heat added, change in internal energy and the work done by a closed cycle process, then :

On a new scale of temperature (which is linear) and called the W scale, the freezing and boiling points of water are 39° W and 239° W respectively. What will be the temperature on the new scale, corresponding to a temperature of 39°C on the Celsius scale ?

At 10°C the value of the density of a fixed mass of an ideal gas divided by its pressure is x. At 110°C this ratio is -

If a gas expands at constant temperature, it indicates that :

Which of the following are not state functions? (I) q+w (II) q (III) w (IV) H⁻TS

A black body is at 727° C. It emits energy at a rate which is proportional to

An engine has an efficiency of 1/6. When the temperature of sink is reduced by 62°C, its efficiency is doubled. Temperature of the source is

If the cold junction of a thermo-couple is kept at 0°C and the hot junction is kept at $\text{T}^\circ\text{C}$ then the relation between neutral temperature $(\text{T}_\text{n})$ and temperature of inversion $(\text{T}_\text{i})$ is

Assuming the sun to have a spherical outer surface of radius r, radiating like a black body at temperature t°C, the power received by a unit surface, (normal to the incident rays) at a distance R from the centre of the sun iswhere $\sigma$ is the Stefan's constant.

Consider the following reactions: (i) H⁺(aq) + OH⁻(aq) → H₂O(l); [ΔH = -X₁ kJ mol⁻¹] (ii) H₂(g) + 1/2 Ω₂(g) → H₂O(l); [ΔH = -X₂ kJ mol⁻¹] (iii) CO₂(g) + H₂(g) → CO(g) + H₂O; [ΔH = -X₃ kJ mol⁻¹] (iv) C₂H₂(g) + 5/2 Ω₂(g) → 2CO₂(g) + H₂O(l); [ΔH = -X₄ kJ mol⁻¹] Enthalpy of formation of H₂O(l) is

A Carnot engine whose sink is at 300 K has an efficiency of 40%. By how much should the temperature of source be increased so as to increase its efficiency by 50% of original efficiency?

The molar specific heat at constant pressure of an ideal gas is (7/2)R. The ratio of specific heat at constant pressure to that at constant volume is:

Identify the correct statement for change of Gibbs energy for a system (ΔGSystem) at constant temperature and pressure:

Assume each reaction is carried out in an open container. For which reaction will ΔH = ΔE?

The enthalpy and entropy change for the reaction: Br₂(l) + Cl₂(g) → 2BrCl(g) are 30 kJ mol⁻¹ and 105 J K⁻¹ mol⁻¹ respectively. The temperature at which the reaction will be in equilibrium is:

Which of the following processes is reversible?

An ideal gas heat engine operates in Carnot cycle between 227°C and 127°C. It absorbs 6 × 10⁴ cal of heat at higher temperature. Amount of heat converted to work is:

A reaction occurs spontaneously if:

Which of the following pairs of a chemical reaction is certain to result in a spontaneous reaction?

MgO(s) + 2HCl(aq) → MgCl₂(aq) + H₂O(l) will be:

One mole of an ideal gas at an initial temperature of T K does 6 R joules of work adiabatically. If the ratio of specific heats of this gas at constant pressure and at constant volume is $\frac{5}{3}$, the final temperature of gas will be :-

Considering entropy (S) as a thermodynamic parameter, the criterion for the spontaneity of any process is :-

An ideal gas heat engine operates in a carnot cycle between 227°C and 127°C. It absorbs 6 kcal at the higher temperature. The amount of heat (in kcal) converted into work is equal to -

The densities of graphite and diamond at 298 K are 2.25 and 3.31 g cm⁻³, respectively. If the standard free energy difference (ΔG°) is equal to 1895 J mol⁻¹, the pressure at which graphite will be transformed into diamond at 298 K is -

What is the entropy change (in JK⁻¹ mol⁻¹) when one mole of ice is converted into water at 0°C ? (The enthalpy change for the conversion of ice to liquid water is 6.0 KJ mol⁻¹ at 0°C)

The molar heat capacity of water at constant pressure, $C_p$, is 75 $\text{JK}^{-1} \text{mol}^{-1}$. When 1.0 KJ of heat is supplied to 100 g of water which is free to expand, the increase in temperature of water is:

The Wien's displacement law express relation between :-