CBSE Class 7 Science Chapter-5 Important Questions - Free PDF Download
FAQs on Important Questions for CBSE Class 7 Science Chapter 5 - Physical and Chemical Changes
1. How many questions are present in Chapter 5 of Class 7 Science?
In the textbook, questions are given at the end of each chapter. Writing answers to these questions help you to gauge your level of understanding of the concept taught. At the same time, it also encourages you to think and recall. All of these skills will be required in every exam that you write. There are 12 questions given at the end of Chapter 5 of Class 7. Extra four questions are given for the purpose of extended learning.
2. What are the important topics in the Chapter 5 of NCERT Solutions for Class 7 Science?
Chapter 5 of Class 7 explains the difference between physical and chemical changes. We come across several of these changes but we can hardly notice them. It is important to understand the concepts of physical and chemical changes and the difference between them. It is also crucial that you memorize some of the equations that you can cite as examples in the exam. Understand the process of rusting, galvanization and crystallization. Make short notes on them. They will come in handy.
3. Explain the process of rusting with the help of an equation.
Iron is a meal that is of immense significance. Discovery of iron thousands of years back has revolutionized our way of life. Iron is present in the house we live in, buildings we work or study in, the cars we travel in and our highways and airplanes. Oxygen and water present in the environment reacts with the iron. When the moisture in the air is high, rusting gathers pace. The process of rusting can also be explained by the equation: Iron + Oxygen + Water -> Rusting.
4. What is galvanisation and why is it needed?
Galvanization is the process in which a layer of zinc is deposited on iron to prevent it from rusting. A layer of zinc prevents the molecules of oxygen and water from coming in contact with the iron. One can also apply paint or grease. Galvanization is needed because iron is an important part of all of our infrastructures. Rusting destroys the quality of the infrastructure and also weakens it. Rusting causes monetary loss as a huge amount of money is invested in buildings, houses, highways, etc.
5. Do I have to practice questions of Chapter 5 Class 7 Science?
Chapter 5 of Class 7 introduces you to the concept of physical and chemical changes. The concept forms the basis of your higher classes. You will be introduced to several concepts in-depth in your higher classes that will be building upon this chapter’s foundation. Practising questions given in the textbook helps you to analyze how well you have understood the concept. The more questions you practice, the more your understanding will be consolidated. Do not cram the information given. Understand the basics and then practice the questions and revise.
