Tiêu đề Work Sheet - 2 (Thermodynamics).pdf ✅

Single correct Q.1 A definite amount of an ideal gas ( =1.5) undergoes a change of state in which heat exchange is equal to work done (q = w). Molar heat capacity of the gas is : (A) 2R (B) 3R (C) R (D)Infinite Q.2 When two equal sized pieces of the same metal at different temperatures Th (hot piece) and Tc (cold piece) are brought into contact into thermal contact and isolated from it's surrounding. The total change in entropyof system is given by (A) C ln c hc T2  TT (B) Cln 1 2 T T (C) Cln ch 2 hc T.T2  )TT( (D) C ln ch 2 hc T.T4  )TT( Q.3 Which of the options contain correct set of parameters which are both amount and path independent parameters. (I) Internal energy (II) Specificenthalpy (III) Heat exchange at constant pressure condition (IV) Molar heat exchange at constant volume condition (V) Temperature (VI) Work involved (A) Only II, IV & V (B)All option except VI (C)All options except III, IV & VI (D) Only II & V Q.4 A real gas is subjected to an adiabatic process causing a change in state from (3 bar, 50 L, 500K) to (5 bar , 40 L, 600 K) against a constant pressure of 4 bar. The magnitude of enthalpy change for the process is : (A) 4000J (B) 5000J (C) 9000J (D) 1000J Q.5 Pressure of 10 moles of an ideal gas is changed from 2 atm to 1 atm against constant external pressure without change in temperature. If surrounding temperature (300 K) and pressure (1 atm) always remains constant then calculate total entropy change (Ssystem + Ssurrounding) for given process. [Given : n2 = 0.70 and R = 8.0 J/mol/K] (A) 56 J/K (B) 14 J/K (C) 16 J/K (D) None of these Q.6 A system contains 1 mole of a monoatomic ideal gas. Now 1 mole of a diatomic nonreacting ideal gas is added into the system at constant volume and temperature. Due to addition of diatomic gas, choose the incorrectstatement, regarding the new system. (A) Enthalpyof system will increase (B)Adiabatic coefficient ( = CP /CV ) of the system will decrease. (C) Internal energyof the system remains constant. (D) Pressure of the system will increase. Q.7 The enthalpy of tetramerization of X in gas phase (4X(g)  X4 (g)) is – 100 kJ/mol at 300 K. The enthalpyof vaporisation for liquid X and X4 are respectively30 kJ/mol and 72 kJ/mol respectively. S for tetramerization of X in liquid phase is – 125 J / K mol at 300 K. What is the G at 300 K for tetramerization of X in liquid phase ? (A) –52 kJ/mol (B) –89.5 kJ/mol (C) –14.5 kJ/mol (D) None of these Q.8 Which of the reaction is expected to be spontaneous at low temperatures and non-spontaneous at high temperatures. (A) Dissociation of PCl5 to give PCl3 and Cl2 (B) Formation of H2O from H2 (g) and O2 (g) (C) Melting of ice (D)Vaporisation of anyvolatile liquid WORK SHEET - 02 THERMODYNAMICS
Q.9 Calculate G(kJ/mole) for the reaction at 300K. N2 (g) + O2 (g) 2NO(g) at an instant where partial pressure of N2 , O2 and NO are 10–1 bar, 10–3 bar, 10–3 bar. If Hf ° NO(g) at 300K = 90.5 kJ/mole and S°f NO(g) at 300K = 12.5J/Kmole [2.303 × R × 300 = 5750J/mole] (A) 173.5 kJ/mole (B) 185 kJ/mole (C) 162 kJ/mole (D) 84.25 kJ/mole Q.10 Select the option which is correct regarding the following statements. Statement-1 : Entropy of system always increases in a spontaneous process. Statement-2 : Adiabatic processwhether reversible or irreversiblewill not cause anychange in entropy of the surroundings. Statement-3 : CO molecule will have residual entropyat 0 K. (A)All the statements are true. (B) Onlystatement-1 is incorrect. (C) Onlystatement-3 is correct. (D) Only statement-2 is correct. Q.11 Which of the following options contain correct set of cases where entropy of system is increasing? Case-I Dissociation of ammonia gas into N2 and H2 gases. Case-II Polymerization process of ethene to form polythene. Case-III Adiabatic irreversible compression of an ideal gas Case-IV Condensation of H2O(vap) to give H2O(l) Case-V Isothermal free expansion of Ideal gas. (A)All the cases (B) Case-I, III and V only (C) Case-I, II and V only (D) Case-I, II, III and V only Q.12 A substance has latent heat of vaporisation (at its boiling point 300 K) = 3 kJ/gm. If molar mass of substance is 40 , then molar entropy change for condensation process will be : (A) 10 J/K (B) 400 J/K (C) – 400 J/K (D) – 10 J/K Q.13 The heat capacity of a diatomic ideal gas subjected to a process such that absolute temperature is proportional to cube of its volume is given by: (A) 2 R5 (B) 2 R7 (C) 6 R17 (D) 2 R3 Assertion Reason Q.14 Statement-1 : Adiabatic free expansion of anysubstance in a closed system will not cause anychange in temperature of the substance. Statement-2 : In adiabatic free expansion of anysubstance in a closed system internal energy will remain constant. (A) Statement-1 is true, statement-2 is true and statement-2 is correct explanation for statement-1. (B)Statement-1istrue,statement-2istrueandstatement-2isNOT thecorrectexplanationforstatement-1. (C) Statement-1 is true, statement-2 is false. (D) Statement-1 is false, statement-2 is true. Assertion Reason Q.15 Statement-1 : Adiabatic free expansion of anysubstance in a closed system will not cause anychange in temperature of the substance. Statement-2 : In adiabatic free expansion of anysubstance in a closed system internal energy will remain constant. (A) Statement-1 is true, statement-2 is true and statement-2 is correct explanation for statement-1. (B)Statement-1istrue,statement-2istrueandstatement-2isNOT thecorrectexplanationforstatement-1. (C) Statement-1 is true, statement-2 is false. (D) Statement-1 is false, statement-2 is true. More than one correct : Q.16 Which of the following process must be spontaneous? (A) Isobaric and Isoentropic process with negative enthalpy change. (B) Isochoric and Isothermal process with negative internal energychange. (C)Aprocess with constant internal energy and Isothermal with an increase in entropy of system. (D)An adiabatic process with constant volume condition and entropyof system increasing.
Q.17 Which of the following option(s) will show a decrease in Gibbs free energy? (A) Combustion of propane at 1 bar and 500K. (B) Vapourisation of anyliquid at 1 atm and above its normal boiling point. (C) Fusion of H2O at 1 atm and 0°C if its normal melting point is 0°C. (D) Vapourisation of H2O at 100°C and 1 bar if its normal boiling point is 100°C. Q.18 Which of the following statements is / are incorrect. (A) Combustion of methane in an adiabatic rigid container will cause no change in temperature of the system. (B) It is possible to have both adiabatic reversible & adiabatic irreversible processes between two states. (C) For a reaction involving onlyideal gases, occurring at constant temperature there will be no change in internal energy. (D) P–V work is always non zero when there is change in volume. Q.19 Assume ideal gas behaviour for all the gases considered & vibrational degrees of freedom to be active. Separate equimolar samples of Ar, H2 , SO2 were subjected to a two step process as mentioned. Initially all are at same state of temperature & pressure. Step I  All undergo reversible adiabatic expansion to attain same final volume, which is double the original volume therebycausing the decreases in their temperature. Step II  After step I all are given appropriate amount of heat isochoricallyto restore the original temperature. Mark the correct option (s). (A) Due to step I only, the decrease in temperature will be maximum forAr (B) During step II, heat given will be maximum for SO2 (C) There will be no net change in internal energy for any of the gas after both the steps of process are completed. (D) The P–V graph ofAr & H2 will be different for overall process. Subjective Q.20 0.5 mole each of two ideal gasesA(Cv = 2 3 R) and B (Cv = 2 5 R) are taken in a container and expanded reversibly and adiabatically from V = 1 L to V = 4 L starting from initial temperature T = 300 K. Find |H| for the process in (Cal/mol). Q.21 A system containing an ideal gas ( = 1.5) at 10 bar, 1 L and 300K undergoes expansion upto 4L. Calculate heat exchange of the system (in J) if process is carried out at a constant external pressure of 1 bar and final pressure becomes equal to 5 bar. Q.22 One mole of an ideal monoatomic gasis carried through thereversible cycle of thegiven figure consisting of stepA,B and C and involving state 1,2 and 3. Fill in the blank space in the tablegiven below assuming reversible steps. State P V T 1 2 3 C B A ΔHΔEwqprocessofNameStep
Q.23 When 1 mole of ice melt at 0°C and at constant pressure of 1 atm. 1440 calories of heat are absorbed by the system. The molar volumes of ice and water are 0.0196 and 0.0180 litre respectively. Calculate H and U for the reaction. Q.24 The molar enthalpyof vaporization of benzene at its boiling point (353 K) is 30.84 kJmol–1 What is the molar internal energy change? For how long would a 12 volt source need to supply a 0.5Acurrent in order to vaporise 7.8 g of the sample at its boiling point ? Q.25 20.0 dm3 of an ideal gas (diatomic Cv, m = 5R/2) at 673 K and 0.7 MPa expands until pressure of the gas is 0.2 MPa. Calculate q,w,U and H for the process if the expansion is:[Given:(7/2)5/7 = 2.447] (i) Isothermal and reversible (ii)Adiabatic and reversible. (iii) Isothermal and adiabatic (iv)Against 0.2 MPa and adiabatic (v)Against 0.2 MPa and isothermal. Q.26 ContainerAcontaining one mole of He is connected with Container B containing 2 moles of Ne at the same temperature and pressure. Calculate Smixing .[Given:R = 2 Cal K–1 mol–1 ; ln3 = 1 ; ln2 = 0.70] [Report your answer by multiplying it with 100] Q.27 The equilibrium constant of the reaction 2C3H6 (g) C2H4 (g) + C4H8 (g) is found to fit the expression lnK eq = –1.04 – T / K 1088 (where T/K is temperature expressed in Kelvin scale) Calculate the standard reaction enthalpy and entropy at 400 K. Q.28 Asubstance undergoes a change represented as shown A(l) [1 bar, 300 K] A(s) [1 bar, 300 K]. From thegiven information, calculate magnitudeof change in internalenergy(in Joules) when1 moles of A(l)solidifies. Information : (i) Standard melting point ofA(s) is 300 K. (ii) Latent heat of fusion ofAis 0.01 kJ/gm. (iii) Specific volume ofA(s) is 100 ml/g andA(l) is 120 ml/gm. (iv) Molar mass ofAis 50 gm / mole. Q.29 One mole of a monoatomic ideal gas is subjected to a process as shown. Calculate the maximum temperature obtained during the process (in Kelvin) Isothermal B D A C 3 atm 2 atm 1 atm 1l 2l 6l P [CD is isothermal] [If Tmax = R X , then fill X in the OMR sheet. ]