ENERGETICS
Energetics is an important topic for both jee main and advanced
It is a high scoring chapter and a good hold on concepts and
formulae will be enough to score well. Energetics consists of
both thermodynamics and thermochemistry. Thermodynamics
forms an integral part of physics for jee advanced while
thermochemistry is exclusive to chemistry.
Important Points:
1. When energy is transferred as heat, the transfer stimulates
random motion. When a system does work, it stimulates
orderly motion.
2. In chemistry, work done by the system on the surroundings
is given a negative sign.
3. Internal energy does not include the kinetic energy arising
from the motion of a system.
4. Internal energy is a state function.
5. In an ideal gas, the internal energy is independent of the
volume occupied by the gas.
6. Internal energy increases with increase in temperature.
7. Both work and heat are path functions.
Intensive and Extensive properties:
Intensive - Temperature , Density, Resistance, Pressure ,
standard electrode potential , molar volume
Extensive - mass, volume, internal energy , heat capacity ,
enthalpy , entropy, Gibbs energy , mole
Enthalpy:
1. It is the energy supplied as heat at constant pressure.
2. H = U + PV
3. For an ideal gas only , H = U + nRT
4. Enthalpy is a state function
Important formulae :
Thermochemistry:
Important Points:
Note:
Heat of formation of nitrous oxide , nitrogen dioxide , nitric
oxide are positive.
Most stable form of phosphorous at 1 atm is black phosphorous.
Calorific value - It is the value of heat produced by burning
1 gram of fuel.
I have attached 2 questions from P. Bahadur which will
strengthen your hold on thermochemistry.
Third Law of Thermodynamics:
1. At 0 K, the entropy of a pure crystal is 0.
2. However there are exceptions to this. eg. Ice , CO2 etc.
These compounds have some residual entropy.
I am certain that all of you will be comfortable in calculating
work done in the common processes. Hence , i have not covered
this. Remember that the direct formula in the case of adiabatic
process is applicable only in the reversible case. Polytropic
processes will be covered in physics and are generally not
asked in chemistry.
CHEMISTRY IS EASY
Energetics is an important topic for both jee main and advanced
It is a high scoring chapter and a good hold on concepts and
formulae will be enough to score well. Energetics consists of
both thermodynamics and thermochemistry. Thermodynamics
forms an integral part of physics for jee advanced while
thermochemistry is exclusive to chemistry.
Important Points:
1. When energy is transferred as heat, the transfer stimulates
random motion. When a system does work, it stimulates
orderly motion.
2. In chemistry, work done by the system on the surroundings
is given a negative sign.
3. Internal energy does not include the kinetic energy arising
from the motion of a system.
4. Internal energy is a state function.
5. In an ideal gas, the internal energy is independent of the
volume occupied by the gas.
6. Internal energy increases with increase in temperature.
7. Both work and heat are path functions.
Intensive and Extensive properties:
Intensive - Temperature , Density, Resistance, Pressure ,
standard electrode potential , molar volume
Extensive - mass, volume, internal energy , heat capacity ,
enthalpy , entropy, Gibbs energy , mole
Enthalpy:
1. It is the energy supplied as heat at constant pressure.
2. H = U + PV
3. For an ideal gas only , H = U + nRT
4. Enthalpy is a state function
Important formulae :
Thermochemistry:
Important Points:
Note:
Heat of formation of nitrous oxide , nitrogen dioxide , nitric
oxide are positive.
Most stable form of phosphorous at 1 atm is black phosphorous.
Calorific value - It is the value of heat produced by burning
1 gram of fuel.
I have attached 2 questions from P. Bahadur which will
strengthen your hold on thermochemistry.
Third Law of Thermodynamics:
1. At 0 K, the entropy of a pure crystal is 0.
2. However there are exceptions to this. eg. Ice , CO2 etc.
These compounds have some residual entropy.
I am certain that all of you will be comfortable in calculating
work done in the common processes. Hence , i have not covered
this. Remember that the direct formula in the case of adiabatic
process is applicable only in the reversible case. Polytropic
processes will be covered in physics and are generally not
asked in chemistry.
Thank you all for reading the notes for this chapter.
Always remember
CHEMISTRY IS EASY
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