Chemistry · Class 11 · Chapter 5
Thermodynamics
12 lessons 100 min 1 simulations 9 practice questions
Chemical thermodynamics tracks the energy exchanged as heat and work when a system changes, and uses it to decide whether a change can happen on its own. The chapter builds from system and surroundings to the first law, enthalpy and thermochemistry (Hess's law, bond enthalpies, lattice enthalpy), and then to entropy and Gibbs energy, linking the sign of ΔG to spontaneity and to the equilibrium constant used in the next chapter.
What the exam asks
NEET sets numericals on ΔU = q + w with NCERT's sign convention, reversible and irreversible work, the link ΔH = ΔU + ΔngRT, Hess's law and bond-enthalpy calculations, and the temperature at which ΔG changes sign. Conceptual items test state versus path functions, extensive versus intensive properties, and the four sign combinations of ΔH and ΔS. Most lost marks come from sign errors in work, from counting liquid or solid moles in Δng, and from forgetting to convert ΔS from J to kJ.
Lessons
12 lessons · 100 min
1System, surroundings and state functionsNCERT § "Thermodynamic Terms"7 min2Work, heat and the first lawNCERT § "The Internal Energy as a State Function"8 min3Pressure-volume workNCERT § "Applications"9 min4Enthalpy, heat capacity and extensive propertiesNCERT § "Enthalpy, H"7 min5CalorimetryNCERT § "Measurement of ΔU and ΔH: Calorimetry"6 min6Reaction enthalpy, standard states and thermochemical equationsNCERT § "Enthalpy Change, ΔrH of a Reaction – Reaction Enthalpy"6 min7Hess's lawNCERT § "Hess's Law of Constant Heat Summation"6 min8Enthalpies of combustion, atomisation, bonds, lattices, solution and dilutionNCERT § "Enthalpies for Different Types of Reactions"7 min9Spontaneity and entropyNCERT § "Spontaneity"8 min10Gibbs energy and spontaneityNCERT § "Gibbs Energy and Spontaneity"11 min 1 sim11Gibbs energy and equilibriumNCERT § "Gibbs Energy Change and Equilibrium"7 min12Chapter reviewMust-know facts, traps and formulas18 min