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Revision Notes
Chemical Kinetics — Revision Notes
Punjab Board · Class 12 · Chemistry
Chemical Kinetics revision notes for Punjab Board Class 12 Chemistry: 4 topics in quick points. Part of the Punjab Board Class 12 Chemistry syllabus.
44 questions30 flashcards3 formulas & key relations5 concepts
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Key Topics to Revise
1
Rate of a Chemical Reaction
- Rate of reaction = change in concentration of reactant or product per unit time
- Rate of disappearance of reactant R: rate = -Δ[R]/Δt (negative sign because concentration decreases)
- Rate of appearance of product P: rate = +Δ[P]/Δt (positive because concentration increases)
2
Rate Law, Rate Constant and Order of Reaction
- Rate law (rate expression) relates the rate of a reaction to the concentration of reactants
- For aA + bB → cC + dD: Rate = k[A]ˣ[B]ʸ where x and y are determined experimentally
- x and y may or may not be equal to stoichiometric coefficients a and b
3
Molecularity of a Reaction
- Molecularity = number of reacting species (atoms, ions, molecules) that must collide simultaneously in an elementary reaction
- Molecularity is defined ONLY for elementary reactions, NOT for complex reactions
- Unimolecular: 1 species involved — e.g., NH₄NO₂ → N₂ + 2H₂O
4
Integrated Rate Equations
- Integrated rate equations relate concentration to time directly — easier to use than differential equations
- ZERO ORDER: Rate = k[R]⁰ = k (rate is constant, independent of concentration)
- Zero order integrated equation: [R] = [R]₀ - kt
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Full NotesKey Concepts
The rate of a chemical reactionThe rate law (or rate expression)The order of a reactionThe rate constant is the proportionalityElementary reactions occur in a single
Frequently Asked Questions
What are the important topics in Chemical Kinetics for Punjab Board Class 12 Chemistry?
Key topics in Chemical Kinetics include Rate of a Chemical Reaction, Rate Law, Rate Constant and Order of Reaction, Molecularity of a Reaction, Integrated Rate Equations. Study these first, then practise questions on each for the Punjab Board Class 12 board exam.
How should I revise Chemical Kinetics for the Punjab Board Class 12 board exam?
Learn the core ideas first, then work through the 44 practice questions on Chemical Kinetics. Revise definitions regularly and use flashcards for quick recall before the exam.
Sources & Official References
Content is aligned to the official syllabus. Refer to the board website for the latest curriculum.
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