12 th Chemistry: CHEMICAL THERMODYNAMICS

 Pathak's Academy Spectrum 2022

CHEMICAL THERMODYNAMICS

Section A (any 7)(7M)

1. Internal energy of a system of a molecule is determined by

A) Kinetic energy B) Vibrational movement C) Rotational movement D) All of these

2. In the reaction C + O2 → CO2 + Heat. The ΔH is A) Maximum B) Minimum C) Negative D) Positive.

3. Which of the following relationship is correct A) H=U-PV B) H=U+P+V C) H= U+PV D) H=-U+PV

4. For an ideal gas the relationship between internal energy change and enthalpy change is A) ΔH=U.PV B) ΔU=ΔH+P. ΔV C) ΔH=U-P. ΔV D) ΔH=ΔU+ΔNrt

5. The enthalpies of all elements in their standard states are A) Unity B) Zero C) Less than Zero D) Different for each element

6. All irreversible processes are A) Non-spontaneous B) In equilibrium C) Isothermal D) Spontaneous

7. An endothermic reaction is allowed to takes place rapidly in air. The temperature of the surrounding air A) Increases B) decreases C) Remains same D) Cannot be predicted

8. Which of the following process is reversible A) Evaporation of water at 100oC and 1atm pressure B) Melting of ice at 10oC C) Mixing of two gases by diffusion D) Non of these

9. ΔU of combustion of methane is –x KJ mol-1. The value of ΔHo is A) Equal to ΔU B) Greater than ΔU C) Less than ΔU D) Equal to zero

Q2 Define (4M)

a) Enthalpy b) Enthalpy of fusion c) Enthalpy of vaporization d) Enthalpy of atomization e) Enthalpy of ionization

Section B

I) What is Entropy? Describe with example (2M)

II) State Third law of Thermodynamics (2MSSection C 

(Any 3)(3X3= 9M)

I) Obtained relationship between ΔH and ΔU for reaction 

II)Define and explain Enthalpy of sublimation with example                         

III) Derive relationship between Bond enthalpy and enthalpy of a chemical reaction

IV) State Hess’s law of constant heat summation with eg.