Class 7 Science
Physical and Chemical Changes
Question 1.
Any alteration of a substance from its original shape, size and state is known as a _______.
Question 2.
Give some examples of reversible changes and irreversible changes.
Question 3.
One should eat freshly cut apple. Why?
Question 4.
What is a physical change? Give some examples of physical changes. Also, state why they are physical changes.
Question 5.
What kind of change is cloud formation?
Question 6.
What is a chemical change?
Question 7.
What is rust? What is rusting of iron?
Question 8.
Explain rusting of copper.
Question 9.
Why silver articles get tarnished?
Question 10.
Give two ways to prevent rusting of iron?
Question 11.
What are physical properties?
Question 12.
In _______ change no new substance is formed.
Question 13.
Which one of the following is a chemical change?
(a) Twinkling of stars
(b) Cooking of vegetables
(c) Cutting of fruits
(d) Boiling of water
Question 14.
Write the chemical equation for burning of magnesium ribbon.
Question 15.
Write the chemical equation for formation of magnesium hydroxide by mixing magnesium with water.
Question 16.
Dissolve about a teaspoonful of copper sulphate (blue vitriol or neela thotha) in about half a cup of water in a glass tumbler or a beaker. Add a few drops of dilute sulphuric acid to the solution. You should get a blue coloured solution.
When you add an iron nail, the colour of the solution turns green. What do you think might be the reason?
a. Formation of iron sulphate
b. Reaction between iron and sulphuric acid changes the colour of the solution.
c. Reaction between iron and copper sulphate changes the colour of the solution.
d. Both a and c.
Question 17.
When iron is dipped in a copper sulphate solution, iron displaces the copper from its solution and forms iron sulphate. In addition, a brown layer can be seen on the iron nail. what is it?
a. Rust
b. Copper
c. Either a or b
d. Neither a nor b
Question 18.
Passing carbon-dioxide through lime water produces _________.
a. CaCO3
b. [Ca(OH)2]
c. CaO
d. None of them
Question 19.
What are the characteristics of chemical changes?
Question 20.
State whether the given sentence is true or false.
For rusting, the presence of both oxygen and water (or water vapour) is essential.
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All About Daily Practice Problems on Class 7 Science Physical and Chemical Changes NCERT Chapter 6
Our Daily Practice Problems (DPPs) offer a diverse range of question types, including Multiple Choice Questions (MCQs) as well as short and long answer types. These questions are categorized into Easy, Moderate, and Difficult levels, allowing students to gradually progress and challenge themselves accordingly. Additionally, comprehensive solutions are provided for each question, available for download in PDF format - Download pdf solutions as well as Download pdf Questions. This approach fosters a holistic learning experience, catering to different learning styles, promoting self-assessment, and improving problem-solving skills. With our well-structured DPPs, students can excel in exams while gaining a deeper understanding of the subject matter. Hope you found the content on Class 7 Science Physical and Chemical Changes NCERT Chapter 6 useful.
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