Chapter 5 of 5
Revision Notes
Physical and Chemical Changes — Revision Notes
Gujarat Board · Class 7 · Science
Physical and Chemical Changes revision notes for Gujarat Board Class 7 Science: 4 topics in quick points. Includes Physical Changes, Chemical Changes.
42 questions5 concepts
Interactive on Super Tutor
Studying Physical and Chemical Changes? Get the full interactive chapter.
Quizzes, flashcards, AI doubt-solver and a step-by-step study plan — built for revision notes and more.
Free trial, no card needed.
Super Tutor
Learn better with visuals Super Tutor pairs illustrations like this with notes and quizzes for Physical and Chemical Changes.
Key Topics to Revise
1
Physical Changes
- A physical change is a change in which only the physical properties of a substance change — such as shape, size, colour, or state.
- No new substance is formed in a physical change.
- Physical changes are generally reversible — the original substance can usually be recovered.
2
Chemical Changes
- A chemical change is a change in which one or more new substances are formed.
- A chemical change is also called a chemical reaction.
- Chemical changes are generally irreversible — the original substance cannot be easily recovered.
3
Rusting of Iron and Its Prevention
- Rusting is a chemical change in which iron reacts with oxygen and water to form rust (iron oxide, Fe₂O₃).
- Both oxygen and water (or moisture) are essential for rusting. If either is absent, rusting does not occur.
- High humidity (moisture in air) makes rusting faster.
4
Crystallisation
- Crystallisation is the process of forming large, pure crystals of a substance from its solution.
- It is a physical change because no new substance is formed — only the physical form changes.
- Salt obtained from evaporation of sea water is not pure, but crystallisation gives pure, large, well-shaped crystals.
Get complete notes with diagrams and examples
Full NotesKey Concepts
A physical change is a changeA chemical change is a changePhysical properties are characteristics ofChemical changes are often accompanied byRusting is a chemical change
Frequently Asked Questions
What are the important topics in Physical and Chemical Changes for Gujarat Board Class 7 Science?
Key topics in Physical and Chemical Changes include Physical Changes, Chemical Changes, Rusting of Iron and Its Prevention, Crystallisation. Study these first, then practise questions on each for Class 7 exams.
How should I revise Physical and Chemical Changes for Class 7 exams?
Learn the core ideas first, then work through the 42 practice questions on Physical and Chemical Changes. 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.
More resources for Physical and Chemical Changes
For serious students
Get the full Physical and Chemical Changes chapter — start free.
Quizzes, flashcards, an AI doubt solver and a study plan for Gujarat Board Class 7 Science. Free to start, no card needed.