Class 11 Chemistry - WEST-BENGAL
Thermodynamics
The chapter 'Thermodynamics' in Class 11 Chemistry under the West Bengal Council of Higher Secondary Education (WBCHSE) introduces students to the study of energy changes accompanying chemical and physical processes. You will learn about systems and surroundings, the First Law of Thermodynamics (conservation of energy), enthalpy, entropy, and Gibbs free energy. Understanding these concepts helps you predict whether a chemical reaction is feasible spontaneously. This chapter is vital for board exams as it features both conceptual questions and numerical problems based on Hess's Law and enthalpy changes, carrying significant weightage in the final exams.
Start Learning FreeKey Concepts
System and Surroundings
A system is the specific part of the universe under observation, while everything else in the universe constitutes its surroundings.
First Law of Thermodynamics
Energy can neither be created nor destroyed, but it can be transformed from one form to another; expressed as delta U = q + w.
Enthalpy (H)
The total heat content of a system at constant pressure, where the change in enthalpy (delta H) equals heat absorbed or released.
Spontaneous Process
A process that can proceed on its own under given conditions without requiring any outside driving force.
Gibbs Free Energy (G)
A thermodynamic property defined as G = H - TS, used to determine the spontaneity of a process at constant temperature and pressure.
Important Formulas
Board Exam Info
In the West Bengal (WBBSE) Class 11 Chemistry examinations, Thermodynamics typically carries around 6 to 8 marks. Questions usually include a mix of 1-mark multiple-choice questions (MCQs), short answer type questions (2-3 marks) defining state functions or intensive properties, and a 3 to 5-mark numerical problem based on enthalpy of reaction, Hess's Law, or Gibbs free energy.
Frequently Asked Questions
What is the difference between state functions and path functions?
State functions depend only on the initial and final state of the system (e.g., pressure, volume, temperature, enthalpy), whereas path functions depend on the path taken to reach that state (e.g., heat and work).
Why is delta G negative for a spontaneous process?
A negative value of Gibbs free energy (delta G < 0) indicates that the total entropy of the system and its surroundings increases, making the process thermodynamically spontaneous.
What is the relation between delta H and delta U?
The relationship is given by the equation delta H = delta U + delta n(g) RT, where delta n(g) is the change in the number of moles of gaseous products and reactants.
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