SEBA Class 7 Science Important Chapter 1 Physical and Chemical Changes Around Us

SEBA Class 7 Science Important Chapter 1 Physical and Chemical Changes Around Us Solutions English Medium As Per SCERT New Syllabus to each chapter is provided in the list so that you can easily browse through different chapters SEBA Class 7 Science Important Chapter 1 Physical and Chemical Changes Around Us Notes and select need one. SEBA Class 7 Science Important Notes in English Download PDF. SCERT Class 7 Science (Amar Bijnan) Additional Solutions in English.

SEBA Class 7 Science Important Chapter 1 Physical and Chemical Changes Around Us

Also, you can read the NCERT book online in these sections Solutions by Expert Teachers as per Central Board of Secondary Education (CBSE) Book guidelines. SCERT Class 7 Science (Amar Bijnan) Extra Solutions in English are part of All Subject Solutions. Here we have given SCERT Class 7 Science Additional Notes in English for All Chapters, You can practice these here.

Physical and Chemical Changes Around Us

Chapter: 1

PART – I

IMPORTANT QUESTION ANSWER

Short Type Question and Answer:

1. What is a physical change? 

Ans: A physical change is a change that involves only physical properties such as shape, size, or state of a substance, where no new substance is formed.

2. What is a chemical change? 

Ans: A chemical change is a process where one or more new substances are created.

3. Give two examples of physical changes. 

Ans: Two examples include tearing paper into pieces and stretching a rubber band.

4. What is rusting? 

Ans: Rusting is a chemical change where iron combines with oxygen and moisture to form a reddish-brown coating called iron oxide (rust).

5. What gas is produced when vinegar reacts with baking soda? 

Ans: The reaction between vinegar and baking soda produces carbon dioxide gas.

6. Define combustion. 

Ans: Combustion is a chemical reaction in which a substance combines with oxygen to release heat and light.

7. What is ignition temperature? 

Ans: Ignition temperature is the lowest temperature at which a substance catches fire.

8. What is weathering? 

Ans: Weathering is the slow natural change where large rocks break down into smaller fragments called sediments.

9. What is erosion? 

Ans: Erosion is the natural process of breaking down and transporting soil and stones from one place to another by forces like water or wind.

10. What is an irreversible change? 

Ans: An irreversible change is one where the original substance cannot be recovered in its initial form, making it permanent in nature.

Fill in the Blanks:

1. Changes that involve only physical properties like shape, size, or state are called ___________.

Ans: Physical changes.

2. In a chemical equation, the starting substances are called _______________.

Ans: Reactants.

3. The white powder formed when magnesium ribbon burns is called ______________.

Ans: Magnesium oxide.

4. ________ is the component in air needed to keep a candle burning.

Ans: Oxygen.

5. Erosion and sedimentation are very ________ processes that take thousands of years to shape the land.

Ans: Slow.

Write True or False:

1. Tearing paper into pieces is a chemical change. 

Ans: False; it is a physical change because it is still paper.

2. The formation of rust is a reversible change. 

Ans: False; it is an irreversible chemical change.

3. A substance can burn even without being directly set on fire if it reaches its ignition temperature.

Ans: True.

4. Antoine Lavoisier is often called the “Father of Modern Chemistry.” 

Ans: True.

5. Cutting down trees is a change that is good for the environment. 

Ans: False; it damages nature and contributes to global warming.