Test: JEE Previous Year Questions- Thermodynamics - JEE MCQ

"Heat cannot be itself flow from a body at lower temperature to a body at higher temperature" is a statement or consequence of –

[AIEEE - 2003]

Which of the following parameters does not characterize the thermodynamic state of matter ?

[AIEEE-2003]

 A Carnot engine takes 3 × 10⁶ cal. of heat from a reservoir at 627ºC, and gives it to a sink at 27º C. The work done by the engine is –

[AIEEE-2003]

 In an irreversible process taking place at constant T and P and in which only pressure-volume work is being done the change in Gibbs free energy (dG) and change in entropy (dS) satisfy the criteria -

 [AIEEE-2003]

The internal energy change when a system goes from state A to B is 40 kJ/mole. If the system goes from A to B by a reversible path and returns to state A by an irreversible path what would be the net change in internal energy

[AIEEE-2003]

The correct relationship between free energy change in a reaction and the corresponding equilibrium constant K_C is –   

[AIEEE-2003]

Which of the following statements is correct for any thermodynamic system ?    

[AIEEE-2004]

An ideal gas expands in volume from 1 × 10^-3 m³ to 1 × 10^-2 m³ at 300 K against a constant pressure of 1 × 10⁵ Nm^-2. The work done is -

[AIEEE-2004]

Which of the following is incorrect regarding the first law of thermodynamics ?

[AIEEE-2005]

The temperature-entropy diagram of a reversible engine cycle is given in the figure. Its efficiency is -

[AIEEE-2005]

A system goes from A to B via two processes I and II as shown in figure. If ΔU₁ and ΔU₂ are the changes in internal energies in the processes I and II respectively, then

[AIEEE-2005]

Consider the reaction : N₂ + 3 H₂ → 2 NH₃ carried out at constant temperature and pressure. If ΔH and ΔU are the enthalpy and internal energy changes for the reaction, which of the following expressions is true ?

[AIEEE-2005]

The work of 146 kJ is performed in order to compress one kilo mole of a gas adiabatically and in this process the temperature of the gas increases by 7º C. The gas is - (R = 8.3 J mol^-1 K^-1) – 

[AIEEE 2006]

An ideal gas is allowed to expand both reversibly and irreversibly in an isolated system. If T_i is the initial temperature and T_f is the final temperature, which of the following statements is correct

[AIEEE 2006]

(ΔH - ΔH) for the formation of carbon monoxide (CO) from its elements at 298 K is (R = 8.314 J K^-1 mol^-1)–

[AIEEE 2006]

A Carnot engine, having an efficiency of h = 1/10 as heat engine, is used as a refrigerator. If the work done on the system is 10 J, the amount of energy absorbed from the reservoir at lower temperature is

 [AIEEE 2007]

 When a system is taken from state i to state f along the path iaf, it is found that Q = 50 cal and W = 20 cal. Along the path ibf Q= 36 cal. W along the path ibf is -

[AIEEE 2007]

In conversion of lime-stone to lime, CaCO₃(s) → CaO(s) + CO₂(g) the values of ΔHº and ΔSº are + 179.1 kJ mol^-1 and 160.2 J/K respectively at 298K and 1 bar. Assuming that ΔHº and ΔSº do not change with temperature, temperature above which conversion of limestone to lime will be spontaneous is-

[ AIEEE 2007]

Assuming that water vapour is an ideal gas, the internal energy change(ΔU) when 1 mol of water is vapourised at 1 bar pressure and 100°C, (Given : Molar enthalpy of vapourisation of water at 1 bar and 373 K = 41 kJ mol^-1 and R = 8.3 J mol^-1K^-1 ) will be -

[AIEEE 2007]

Identify the correct statement regarding a spontaneous process –

 [AIEEE 2007]

Standard entropy of X₂, Y₂ and XY₃ are 60, 40 and 50 J K^-1 mol^-1, respectively. For the reaction, X₂ + Y₂ – XY₃ DH = – 30 kJ, to be at equilibrium, the temperature will b[AIEEE 2008]

 In a fuel cell methanol is used as fuel and oxygen gas is used as an oxidizer. The reaction is CH₃OH(l) + O₂(g) → CO₂(g) + 2H₂O(l) At 298 K standard Gibb's energies of formation for CH₃OH(l), H₂O(l) and CO₂(g) are –166.2, –237.2 and –394.4 kJ mol^-1 respectively. If standard enthalpy of combustion of methanol is –726 kJ mol^-1, efficiency of the fuel cell will be-  

[AIEEE 2009]

A diatomic ideal gas is used in a Carnot engine as the working substance. If during the adiabatic expansion part of the cycle the volume of the gas increases from V to 32 V, the efficiency of the engine is-

 For a particular reversible reaction at temperature T, ΔH and ΔS were found to be both +ve. If is the temperature at equilibrium, the reaction would be spontaneous when    

[AIEEE 2010]

The entropy change involved in the isothermal reversible expansion of 2 moles of an ideal gas from a volume of 10 dm³ to a volume of 100 dm³ at 27º C is :

[AIEEE 2011]

 In view of the signs of D_rG° for the following reactions :

PbO₂ + Pb → 2 PbO, D_rG° < 0

SnO₂ + Sn → 2 SnO, D_rG° > 0,

which oxidation states are more characteristic for lead and tin ?       [AIEEE 2011]

 The incorrect expression among the following is –

 [AIEEE-2012]