JEE Main Thermodynamics — practice questions
92 free MCQs with worked solutions. Tap any question for the answer + explanation, or practice them all in the app.
Practice JEE Main Thermodynamics in the app →The first law of thermodynamics is mathematically expressed as:In an isothermal process for an ideal gas, which thermodynamic quantity remains constant?For an ideal gas expanding isothermally from volume $V_1$ to $V_2$ at temperature $T$, the work done by the gaFor an adiabatic process involving an ideal gas, which quantity is constant?A Carnot engine operates between a hot reservoir at $T_1 = 500$ K and a cold reservoir at $T_2 = 300$ K. The eFor an ideal gas, the relation between molar heat capacities is $C_p - C_v = R$. Why is $C_p$ always greater tThe first law of thermodynamics is essentially a statement of:Work done in an isothermal process for ideal gas:In an adiabatic process, the heat exchanged with surroundings is:The ratio Cp/Cv is denoted by:For an ideal gas, Cp − Cv equals:In an ISOCHORIC process, work done equals:For an adiabatic process on ideal gas: PV^γ = ?Internal energy change ΔU for an ideal gas depends ONLY on:In an isothermal expansion of ideal gas, the work done BY the gas is +500 J. The heat absorbed by the gas is:A monatomic ideal gas has γ = 5/3. For an adiabatic process, P₁V₁^γ = P₂V₂^γ. If V₂ = 8V₁, find P₂/P₁:1 mole of ideal gas (Cv = 3R/2) is heated at constant volume from 300 K to 600 K. Heat absorbed:For a monatomic ideal gas in isobaric expansion from V₁ to 3V₁, find ΔT/T₁:In a cyclic process, ΔU equals:The slope of an isothermal curve in PV diagram (dP/dV)_T equals:The slope of an adiabatic curve in PV diagram (dP/dV)_adiabatic equals:For a Carnot engine operating between T_h = 600 K and T_c = 300 K, efficiency is:A gas absorbs 500 J of heat and does 200 J of work. Change in internal energy:For a diatomic ideal gas (γ = 7/5), molar Cv equals:Isothermal bulk modulus of an ideal gas equals:Adiabatic bulk modulus of ideal gas equals:In a free expansion of ideal gas (into vacuum), the temperature:An ideal gas undergoes isobaric expansion. Q = 100 J, W = 40 J. Find ΔU:For an adiabatic process of an ideal gas, TV^(γ-1) = constant. If T₁ = 300 K and V₂ = 2V₁ for γ = 5/3, then T₂In a Carnot cycle, heat absorbed at hot reservoir is 1000 J. Efficiency 25%. Heat rejected at cold reservoir:For polytropic process PV^n = constant, n = 0 means:Two identical containers contain ideal gas at temperatures T₁ and T₂. The walls suddenly become porous, gases In which process is heat capacity infinite for ideal gas?A heat engine operates with 20% efficiency between two reservoirs. If T_h = 500 K, find T_c (for maximum/CarnoAn ideal gas undergoes isothermal expansion at 300 K from V = 1 to V = 2. Heat absorbed (n = 1):A diatomic ideal gas at 27°C is compressed adiabatically to ½ its volume. Find final temperature (γ = 7/5):Per NCERT §5.1.2, an OPEN system exchanges what with its surroundings, in contrast to a closed or isolated onePer NCERT §5.1.2, an ISOLATED system is exemplified by which container?Per NCERT §5.1.4, the INTERNAL ENERGY U of a system is classified as which kind of property?Per NCERT eqn 5.1, the FIRST LAW of thermodynamics is expressed as which equation, with sign conventions?Per NCERT eqn 5.2, the pressure-volume WORK done on a gas at constant external pressure p_ex is given by whichPer NCERT §5.2.1 + eqn 5.5, for an isothermal REVERSIBLE expansion of n mol of an ideal gas from V_i to V_f, wPer NCERT §5.2.1 (free expansion), what is the work done in FREE EXPANSION of an ideal gas into vacuum (p_ex =Per NCERT §5.2.1, a process is called REVERSIBLE if it satisfies which condition?Per NCERT §5.2.1, for an ADIABATIC process (no heat exchange, q = 0), the first law reduces to which form?Per NCERT §5.2.1, for an ISOTHERMAL IRREVERSIBLE expansion of an ideal gas at constant external pressure p_ex,Per NCERT §5.2.1, at CONSTANT VOLUME (ΔV = 0), the first law simplifies to which?Per NCERT Problem 5.2, when 2 L of an ideal gas at 10 atm expands isothermally into VACUUM to total volume 10 Per NCERT §5.2.2 + eqn 5.7, the ENTHALPY H is defined as which quantity?Per NCERT eqn 5.10, the relationship between ΔH and ΔU for a gaseous reaction is which?Per NCERT Problem 5.5, for vaporisation of 1 mol of water at 100 °C and 1 bar, given ΔH = 41 kJ/mol, what is ΔPer NCERT eqn 5.13, the relationship between C_p and C_v for an ideal gas is which?Per NCERT §5.4(a), the STANDARD STATE of a substance at a specified temperature is which?Per NCERT Table 5.1, the standard enthalpies of fusion and vaporisation of WATER are which?Per NCERT §5.4(c), what is the CONVENTION for the standard enthalpy of formation Δ_f H° of an ELEMENT in its rPer NCERT Table 5.2, Δ_f H° of methane CH₄(g) is which value?Per NCERT eqn 5.15, the standard enthalpy of REACTION from formation enthalpies is computed as which?Per NCERT §5.4(e), HESS'S LAW of constant heat summation states which?Per NCERT §5.4(e) (worked example), given C+O₂→CO₂ ΔH = −393.5 and CO+½O₂→CO₂ ΔH = −283.0 kJ/mol, what is Δ_f Per NCERT §5.4(d) (thermochemical equations), if a chemical equation is REVERSED, what happens to Δ_r H°?Per NCERT §5.5(a), the STANDARD ENTHALPY OF COMBUSTION Δ_c H° of butane (cooking gas) is which?Per NCERT §5.5(a), the standard enthalpy of combustion of GLUCOSE (C₆H₁₂O₆) is which?Per NCERT §5.5(b), the ENTHALPY OF ATOMIZATION Δ_a H° of dihydrogen is which value, and how does it relate to Per NCERT §5.5(c), in CH₄ atomisation requires 1665 kJ/mol. What is the MEAN C-H bond enthalpy?Per NCERT eqn 5.17, the standard enthalpy of a GAS-phase reaction from bond enthalpies is approximated as whicPer NCERT Table 5.3(b), the bond enthalpy of N≡N triple bond is which value — among the highest known for diatPer NCERT §5.5(d), the LATTICE ENTHALPY of an ionic compound is defined as the enthalpy change for which procePer NCERT §5.5(d), the BORN-HABER cycle for NaCl uses Hess's law and includes which steps?Per NCERT §5.5(e), the enthalpy of SOLUTION Δ_sol H° of an ionic compound in water is decomposed as which sum?Per NCERT §5.3, a BOMB CALORIMETER measures which thermodynamic quantity?Per NCERT Problem 5.6, 1 g graphite burnt in a bomb calorimeter (heat capacity 20.7 kJ/K) raises temperature bPer NCERT Table 5.2, the Δ_f H° of C(diamond) is which value (note: NOT zero, because graphite — not diamond —Per NCERT §5.6, a SPONTANEOUS process is best defined as which of the following?Per NCERT §5.6(b), ENTROPY S is best described as which?Per NCERT eqn 5.18, the entropy change for a REVERSIBLE process is given by which expression?Per NCERT eqn 5.19, for a SPONTANEOUS process the TOTAL entropy change (system + surroundings) obeys which inePer NCERT Problem 5.10, in which of the following processes does entropy DECREASE?Per NCERT §5.6(e), the THIRD LAW of thermodynamics states which?Per NCERT §5.6(d), the SECOND LAW of thermodynamics, in entropy form, states which?Per NCERT eqn 5.20-21, GIBBS energy G and its change ΔG at constant T are given by which expressions?Per NCERT §5.6(c) (criteria), the sign of ΔG for a SPONTANEOUS process at constant T and p is which?Per NCERT Table 5.4, a reaction with ΔH < 0 AND ΔS > 0 is spontaneous under which condition?Per NCERT Table 5.4, a reaction with ΔH > 0 AND ΔS > 0 is spontaneous under which condition?Per NCERT §5.7 eqn 5.23, the relation between ΔG° and equilibrium constant K is which?A gas absorbs $200$ J of heat and does $80$ J of work on its surroundings. The change in internal energy is:A pump compresses gas very fast, so no heat escapes. The process is:A Carnot engine works between $T_h = 400$ K and $T_c = 300$ K. Its efficiency is:A glass of cold lassi placed on a kitchen counter eventually warms to room temperature. The second law of therFor a reaction occurring at constant pressure in an open beaker, the heat absorbed equals:Hess's law states that the standard enthalpy change for a reaction:Among solid ice, liquid water, and water vapour at the same temperature, entropy is:A reaction has $\Delta H = -100$ kJ and $\Delta S = +200$ J/K. At $T = 298$ K, $\Delta G$ is: