These MP Board Class 11th Chemistry Notes for Chapter 6 Thermodynamics help students to get a brief overview of all the concepts.

MP Board Class 11th Chemistry Notes Chapter 6 Thermodynamics

→ Energy : Capacity to do work is Energy.

→ Chemical energetics : Branch of chemistry which deals with the energy changes associated with chemical reaction is called chemical energetics.

→ In chemical reaction energy is used in breaking the bonds of reactant compounds whereas energy is released in the making of new bonds in product compounds.

MP Board Class 11th Chemistry Notes Chapter 6 Thermodynamics

→ Exothermic reactions : Reactions in which energy is released.
A + B → C + D,+ Q or – ΔH

→ Endothermic reactions : Reactions in which energy is absorbed.
A + B → C + D,- Q or + Δ H

→ Internal energy is the sum of various types of energies of molecules of a substance. It is a state function.

→ Internal energy change (Δ E): Heat given to a system at constant temperature and constant volume is equal to increase in its Internal Energy (ΔE = qv).

→ Enthalpy (H) : Enthalpy of any system is the sum of internal energy and product of pressure and volume, i.e., H = E + PV.

→ Enthalpy change (ΔH) : Enthalpy change is the difference of enthalpies of products and reactants in a chemical reaction, i.e.,
ΔH = H(products) – H(reactants)

Enthalpy change is also related with change in internal energy and work done, i.e.,
ΔH = ΔE + PΔV

MP Board Class 11th Chemistry Notes Chapter 6 Thermodynamics

Heat (qp) given to the system at constant pressure is equal to increase in enthalpy of the system ΔH = qp

→ First law of thermodynamics : According to it, Total energy of the universe is always con¬served. Mathematically AE = q + W

→ Heat of reaction : Is the enthalpy change in a chemical reaction (Difference in Enthalpy of products and reactants).

→ Heat of neutralization : Energy produced in neutralization of one gram equivalent of acid by one gram equivalent of base at constant temperature.
For a strong acid and strong base value of ΔH = -57.1 kJ.

→ Heat of combustion: At constant pressure, when one mole of any substance completely reacts with excess of oxygen, energy released in this process is called heat of combustion.

→ Heat of formation: When 1 mole of substance is formed from its constituent elements in their stable states, the energy absorbed or released is called heat of formation.

→ Heat of fusion : Enthalpy change when one mole of solid substance is liquified, is called heat
of fusion (Hfussion)

→ Heat of vaporization : When one mole liquid substance changes into gaseous state, enthalpy change in this process is called heat of vaporization (Hvap)

→ Hess’s law: The enthalpy change in a chemical process is always same whether the process is carried out in one or in several steps.

MP Board Class 11th Chemistry Notes Chapter 6 Thermodynamics

→ Bond energy: The average energy required to break the bonds present in 1 mole of a gaseous molecule is called bond energy.

→ Endothermic Reaction : Absorption of heat in a reaction ΔH = +Ve .
→ Enthalpy (H) is a state function :
H = E + PV
ΔH = ΔE + PΔV .
qp, =ΔH
ΔH = ΔE + ΔnRT
gv = ΔE
4.18 x 107 Erg = 1 calorie

→ Entropy change (ΔS) = \(\frac{q_{\mathrm{rev}}}{\mathrm{T}}\)

→ For spontaneous process, ΔG is negative.

→ If the process is in equilibrium, ΔS is zero.

→ Free energy, G = H-TS and AG = ΔH-TΔS.

→ Heat of reaction at constant volume : Heat of reaction at constant volume is equal to the difference of internal energy of products (EP) and internal energy of reactants (ER). /.e.,
ΔE = Ep – ER = qv

MP Board Class 11th Chemistry Notes Chapter 6 Thermodynamics

→ Heat of reaction at constant pressure (qp) : Heat of reaction at constant pressure is equal to the heat absorbed or evolved when all moles of reactants react completely at constant pressure.

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