Chapter 6- Physical and Chemical Changes

Worksheet for class 7 Science Chapter 6- Physical and Chemical Changes

This page consists of MCQ-based questions with detailed solutions for Chapter 6- Physical and Chemical Changes of class 7 science prepared by HT experts. Check out all the worksheets for class 7 science. Do solve NCERT textbook with the help of NCERT solutions for class 7 science. 

Questions and answers for CBSE class 7 science Chapter 6- Physical and Chemical Changes Set-1

Q.1.Galvanisation is a process of depositing a layer of 

(a) copper on iron.

(b) zinc on iron.

(c) aluminium on iron.

(d) nickel on iron.

Ans. (b) 

Solution- Galvanisation is a process of depositing a layer of zinc on iron to protect it from rusting.

Q2.Pure salt is obtained by

(a) evaporation.

(b) sublimation.

(c) filtration.

(d) crystallisation.

Ans. (d) 

Solution- The process of separation of pure crystals of a substance from its hot and concentrated solution on cooling is known as crystallisation. Crystal is a solid form in which atoms are arranged in a regular pattern. Crystallisation is a physical change.

Q.3. When an iron nail is added to a blue-coloured copper sulphate solution, it turns

(a) green.

(b) yellow.

(c) black.

(d) white.

Ans. (a) 

Solution- The reaction in which more reactive metal displaces less reactive metal from its compound in an aqueous solution is called displacement reaction, e.g., when an iron nail is dipped in copper sulphate solution (blue), then the iron being more reactive displaces copper from its solution and forms ferrous sulphate solution (green colour). 

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