Скачать или смотреть [Part 4] THERMODYAMICS | CLASS XI | CBSE |Enthalpy (ΔH)Relation between ΔU and ΔH Numerical Problems

Topic :-
Conclusion of FLOT
Enthalpy (ΔH)
Relation between ΔU and ΔH
Numerical Problems
Isochoric Process
Isothermal Process
Isobaric process (Enthalpy)
At constant pressure, the heat released or absorbed (qp)by the system is equal to the change in enthalpy of system (ΔH).
At constant volume, the heat released or absorbed (qv)by the system is equal to the change in internal energy of system (ΔU).
MCQs (1 mark each)

Assertion–Reason (1 mark)
Assertion (A): For the combustion of glucose, ΔH and ΔU are nearly equal.Reason (R): Because in this reaction, Δn (change in moles of gases) is almost zero.
Numerical Questions ( 2 marks)
Q1. Calculate ΔH for the reaction at 300 K if ΔU = −200 kJ and Δn = 2.(Use R = 8.314 J mol⁻¹ K⁻¹)
Q2. For the reaction:N₂(g) + 3 H₂(g) → 2 NH₃(g)At 298 K, ΔU = −92.4 kJ. Find ΔH.
Q3. If ΔH = −500 kJ, ΔU = −480 kJ at 298 K, find Δn.
Q4. For the reaction:C(s) + O₂(g) → CO₂(g)At 298 K, ΔU = −394 kJ. Calculate ΔH.


Q1. If water vapour is assumed to be a perfect gas, molar enthalpy change for vapourisation of 1 mol of water at 1bar and 100°C is 41kJ mol–1. Calculate the internal energy change, when 1 mol of water is vapourised at 1 bar pressure and 100°C.
Q2. A system absorb 600 J of heat and work equivalent to 300 J is done on it surroundings. what will be the change in the internal energy of the system ?
Q3. An ideal gas expands against a constant external pressure of 2 atm from 20 L to 40 L and absorb 10 kJ of heat from the surrounding. what is the change in the internal energy of the system. (Given 1 atm.L = 101.3 J)