Class 11 Chemistry — Chapter 5: THERMODYNAMICS

Chapter 5: THERMODYNAMICS is a chapter in Class 11 Chemistry (Part 1), part of the CBSE NCERT curriculum followed by over 25 million students across India. This chapter covers 9 topics including Thermodynamic Systems and Surroundings, State Functions vs. Path Functions, Internal Energy, Heat, and Work. BrainWeave provides free AI-powered explanations — by voice or text, in Hindi or English — with no signup required.

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What you'll learn

▸Thermodynamic Systems and SurroundingsCore concept

systemsurroundingsopen systemclosed systemisolated system
▸State Functions vs. Path FunctionsCore concept

state functionpath functioninternal energypressureheat
▸Internal Energy, Heat, and WorkCore concept

internal energy (U)heat (q)work (w)sign conventionadiabatic
▸First Law of ThermodynamicsCore concept

first lawconservation of energyΔU = q + winternal energy change
▸Enthalpy (H)Core concept

enthalpy (H)heat at constant pressureΔHΔUΔn_gRT
▸Hess's Law of Constant Heat SummationCore concept

Hess's Lawenthalpy of reactionconstant heat summationthermochemical equations
▸Extensive and Intensive Properties

extensive propertiesintensive propertiesmasstemperaturedensity
▸Spontaneity and Entropy (S)Core concept

spontaneous processentropy (S)randomnessdisordersecond law
▸Gibbs Free Energy (G) and SpontaneityCore concept

Gibbs free energy (G)ΔGspontaneityequilibriumΔG = ΔH - TΔS

Chapter Summary

Distinguish between the system, surroundings, and boundary. Classify systems as open, closed, or isolated based on the exchange of energy and matter.

Understand the difference between state functions (e.g., internal energy, enthalpy), which depend only on the initial and final states, and path functions (e.g., heat, work), which depend on the process taken.

Define internal energy (U) as the total energy of a system and understand the sign conventions for heat (q) transferred and work (w) done on or by the system.

State the First Law of Thermodynamics as the principle of conservation of energy and apply its mathematical expression, ΔU = q + w, to solve problems involving energy changes.

Define enthalpy (H) as a thermodynamic property (H = U + pV) and understand its relationship with internal energy (ΔH = ΔU + Δn_gRT). Recognize that ΔH represents the heat exchanged at constant pressure.

Apply Hess's Law to calculate the enthalpy change for a reaction by combining the enthalpy changes of other known reactions, treating them as algebraic equations.

Differentiate between extensive properties, which depend on the amount of substance (e.g., mass, volume), and intensive properties, which are independent of the amount (e.g., temperature, density).

Define a spontaneous process and understand entropy (S) as a measure of molecular randomness or disorder. Know that the total entropy of the universe increases in a spontaneous process.

Use the Gibbs free energy equation (ΔG = ΔH - TΔS) to predict the spontaneity of a chemical reaction under constant temperature and pressure, and its relationship with the equilibrium constant.

Practice Questions from this Chapter

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Explain how a car engine uses energy. Get Solution →
Give a real-world example of an isolated system. Get Solution →
Describe the energy changes when food cooks. Get Solution →
In thermodynamics, what term refers to the part of the universe in which observations are made? Get Solution →
What type of system allows for the exchange of both energy and matter with its surroundings? Get Solution →
What is the thermodynamic term for the wall that separates a system from its surroundings? Get Solution →
Which of the following is an example of an isolated system? Get Solution →
What is an adiabatic process? Get Solution →

Did you know?

💡 A single lightning bolt can contain enough energy to power a house for weeks.
💡 The total amount of energy in the entire universe never changes, it just transforms.
💡 Humans are open systems, constantly exchanging matter and energy with their environment.
💡 Your body converts food's chemical energy into movement and warmth every day.
💡 Heat always flows from hotter objects to colder ones, never in reverse naturally.

Frequently Asked Questions

How many topics are covered in this chapter?

This chapter covers 9 key topics: Thermodynamic Systems and Surroundings, State Functions vs. Path Functions, Internal Energy, Heat, and Work, First Law of Thermodynamics, Enthalpy (H), and more. The BrainWeave AI tutor explains each one with examples.

Is Chapter 5: THERMODYNAMICS important for board exams?

Class 11 is a foundation year. Mastering this chapter now will help you build strong fundamentals for the higher classes.

Can I get NCERT solutions for this chapter in Hindi?

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