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CBSE Guess > Papers > Important Questions > Class XII > 2007 > Chemistry > Thermodynamics
1 MARK QUESTION
- Define bond dissociation energy
- Why is internal energy of system is statefunction.
- How may the state of a thermodynamic system be defined.
- In what ways the internal energy of a system be changed.
- What is the effect of temperature on entropy
- Explain the state of a reaction when d G =0?
- State a chemical reaction when d H and d E are equal?
- State the second law of thermodynamics
- What is average bon dissociation energy for a molecule.
- What is the thermodynamic efficiency of Fuel Cell.
2 MARK QUESTION
- Define the following terms:
[a] State variables of asystem [b] Internal energy of system
- Derive themathematical expression ofthefirst law of thermodynamics for a gaseous system undergoingexpanion at constant pressure.
- State Hess law How is it useul in calculating enthalpy change of a reaction?
- State the third law ofthermodynamics. Define an isolated system.
- Calculate theG for the forward reaction at450 K in the following equilibrium
2NOCl (g) --> 2NO(g) + Cl2 (g)
d H = 77.2 kj/mol d S = 122 J/K?mol at 450 K
3 MARK QUESTION
- Define entahlpy. Show that the change in enthalpy at constant pressure , for a reaction envolving gases is given by the expression
d H = d E +d n RT
- Calculate the free energy change and entropy change per mole when liquid water boils against 1 atmospheric pressure [ for water d H = 2.0723 kj/gm]
- Enthalpy and entropy change of a reaction are 40.63 Kj/mole and 108.8 J/k/mole respectively. Predict the feasibility of the reaction at 300K
- d H & d S for vapourisation of water at 1 atm pressure are 40.63 Kj/mole and 108.8 J/K/mole respectively. Calculate the temperature at which the free energy change for this reaction will be zero. Predict stating reason the sign of free energy change below this temperature.
- State the second law of thermodynamics. The enthalpy change for the formation of ammonia from nitrogen and hydrogen is -92.4 kj/mole Calculate the standard internal energy change at 298 K .
5 MARK QUESTION
- Mention the various thermodynamic conditions for spontaneous occurence of process.\
- Illustrate with an example what is meant by standard free energy change of formation of compound State the relation between standard free energy change and equilibrium constant of a chemical reaction.
The equilibrium constant at 25 C for the process Co 2+ aq + 6NH3 --> [Co(NH3)6]3+ (aq)
is 2.0x10-7 . Calculate the value of d G at 25 C In which direction is the reaction spontaneous when reactants and products are under standard conditions.
- Atomic Structure and Chemical Bonding
- Solid State
- Chemical Kinetics
- P Block Elements
- D and F Block Elements
- Nuclear Chemistry
- Stereo Chemistry
- Organic Functional Group I
- Organic Functional Group II and III
- Surface Chemistry
- Chemistry In Every Day Life
- Practice Paper No.1
- Practice Paper No.2
- Practice Paper No.3
- Practice Paper No.4