Class 7 Science Notes for Physical and Chemical Changes (PDF) – Study Material

Class 7 Science Physical and Chemical Changes – Get here the Notes, Question & Practice Paper of Class 7 Science for topic Physical and Chemical Changes Notes. Physical and Chemical Changes Notes for Class 7 Science are here. You can download the Physical and Chemical Changes Notes PDF to study all the topics in this chapter. Moreover the Class 7 Science notes include chapter summary, definitions, examples, and key pointers for Physical and Chemical Changes. Thus if you are studying class Science (विज्ञान), then the Physical and Chemical Changes notes will help you easily understand the topic and ace it.

Class 7 Science Notes for Physical and Chemical Changes

Physical and Chemical Changes is a critical part in the study of Science. In India, it is taught in class. Therefore the Class 7 Notes for Science topic Physical and Chemical Changes have been compiled by teachers and field experts. They explain the complete chapter of Physical and Chemical Changes in one-shot.

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Physical and Chemical Changes Notes for Class 7 Science

Physical and Chemical Changes Class 7 notes is as follows. You can view the document here and also download it use it anytime for future reference whenever you want to brush up your concepts of Science.

Chapter 5 – Physical and Chemical Changes

Introduction

There are several changes we come across daily e.g dissolving sugar in water, or flattening a metal rod by beating it. These involve changes in the form of the substance. Changes can be classified as:

(i) Physical
(ii) Chemical

Physical properties

Physical properties include size, shape, colour and state (solid/liquid/gas) of a substance.

Physical change

• Any change to the physical properties of a substance is called a physical change.
• Physical changes are usually reversible as no new substance is formed. It is the same substance but with changed physical properties.

Chemical change

• A change in which one or more new substances are formed is called as a chemical change.
• Usually a chemical change involves a chemical reaction, which forms new products.
• Example : Rusting of Iron, or burning wood.

Metallic Oxides

Formation of metal oxides are examples of chemical changes. They are formed by the reaction of oxygen in air.

• Burning of Magnesium ribbon:
• 2Mg + O₂ → 2MgO
• The product formed is the oxide of magnesium, which is in the form of ash. It does not look anything like the magnesium ribbon used for burning.

Reaction of metallic oxides with water

• Reaction of metal oxides with water form metal hydroxides.
• Example dissolving Magnesium oxide in water, by stirring the ash very well with water.
• MgO + H₂O → Mg(OH)₂
• The product formed is basic in nature and turns red litmus paper → blue

Reaction between baking soda and vinegar

When a pinch of baking soda is added to vinegar we hear a hissing sound and observe the formation of bubbles.

• Vinegar (Acetic Acid) + Baking Soda (Sodium bicarbonate) → CO₂ (Carbon dioxide) + Other products
  The carbon dioxide produced during the reaction of Vinegar and baking soda, when passed through lime water gives calcium carbonate, as follows:
• CO₂ + Ca(OH)₂ (lime water) → Calcium Carbonate (CaCO₃) + H₂O
• The calcium carbonate turns lime water milky.

Observations that indicate a chemical change

• Heat or light is absorbed or given out during a chemical reaction.
• Production of sound
• Production of gases or precipitates
• Production of smell
• A colour change may occur

Rusting

• When substances made of Iron are exposed to oxygen and moisture in the atmosphere, it forms a red layer, which is called rust.
• The formation of rust can be represented by the following reaction:
• 4Fe + 3O₂ → 2Fe₂O₃. The chemical formula for rust is Fe₂O₃.nH₂O. More the moisture in the air, quicker the formation of rust.
• Galvanization
  • The process of depositing zinc on the surface of Iron to prevent rusting is called as galvanisation.
  • Example: Iron water pipes are galvanised. Ships are made out of iron which is galvanised. Due to the presence of salts in seawater, the process of rusting is hastened.
    Hence ships need to replace their iron body every year.
• Crystallisation
  • The process of separation of salts from their solution is called as crystallisation. It is a purification technique that purifies seawater or separates crystals from impure samples. It is a physical change.

Candidates who are ambitious to qualify the Class 7 with good score can check this article for Notes, Study Material, Practice Paper. Above we provided the link to access the Notes, Important Question and Practice Paper of Class 7 Science for topic Physical and Chemical Changes.

All Topics Class 7 Science Notes

Chapter wise notes for Science (विज्ञान) are given below.

• Nutrition in Plants
• Nutrition in Animals
• Heat
• Acids, Bases and Salt
• Physical and Chemical Changes
• Respiration in Organism
• Transportation in Animals and Plants
• Reproduction in Plants
• Motion and Time
• Electric Current and Its Effects
• Light
• Forest our Life Line
• Wastewater Story

Class 7 Notes for All Subjects

• Class 7 Maths Notes
• Class 7 Science Notes

NCERT Solutions for Class 7 Science Physical and Chemical Changes

The Physical and Chemical Changes notes here help you solve the questions and answers. Also, you can complete the Class 7 Physical and Chemical Changes worksheet using the same. In addition you will also tackle CBSE Class 7 Science Important Questions with these Class 7 notes.

However if you still need help, then you can use the NCERT Solutions for Class 7 Science Physical and Chemical Changes to get all the answers. Physical and Chemical Changes solutions contain questions, answers, and steps to solve all questions.

Notes for All Classes

• Class 6 Notes
• Class 7 Notes
• Class 8 Notes
• Class 9 Notes
• Class 10 Notes
• Class 11 Notes
• Class 12 Notes

Physical and Chemical Changes Notes for Class 7 Science – An Overview

Name of Topic	Physical and Chemical Changes
Class	6
Subject	Science
All Class 7 Science Notes	Class 7 Science Notes
All Class 7 Notes	Class 7 Notes

Class 7 Physical and Chemical Changes Notes for All Boards

You can use the Class 7 Science notes of Physical and Chemical Changes for all boards.

The education boards in India for which Physical and Chemical Changes notes are relevant are – CBSE, CISCE, AHSEC, CHSE Odisha, CGBSE, HBSE, HPBOSE, PUE Karnataka, MSBSHSE, PSEB, RBSE, TBSE, UPMSP, UBSE, BIEAP, BSEB, GBSHSE, GSEB, JAC, JKBOSE, KBPE, MBOSE, MBSE, MPBSE, NBSE, DGE TN, TSBIE, COHSEM, WBCHSE.

Therefore you can refer to these notes as CBSE, CISCE, AHSEC, CHSE Odisha, CGBSE, HBSE, HPBOSE, PUE Karnataka, MSBSHSE, PSEB, RBSE, TBSE, UPMSP, UBSE, BIEAP, BSEB, GBSHSE, GSEB, JAC, JKBOSE, KBPE, MBOSE, MBSE, MPBSE, NBSE, DGE TN, TSBIE, COHSEM, WBCHSE notes for class Class 7 / Class / Science for the topic Physical and Chemical Changes.