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Class 9 Chemistry Chapter-wise Solutions Click on the links given alongside the chapters:- Chapter 1 The Language of Chemistry:  http://novakidhs.blogspot.com/2022/02/the-language-of-chemistry-class-9.html Chapter 2 Chemical Changes and Reactions:  http://novakidhs.blogspot.com/2022/02/chemical-changes-and-reactions-class-9.html Chapter 3 Water:  http://novakidhs.blogspot.com/2022/02/water-class-9-chemistry-selina-concise.html Chapter 4 Atomic Structure and Chemical Bonding:  http://novakidhs.blogspot.com/2022/02/atomic-structure-and-chemical-bonding.html Chapter 5 The periodic table:  http://novakidhs.blogspot.com/2022/02/the-periodic-table-class-9-chemistry.html Chapter 6 Study of the first Element Hydrogen:  http://novakidhs.blogspot.com/2022/02/study-of-first-element-hydrogen-class-9.html Chapter 7 Study of Gas laws:  http://novakidhs.blogspot.com/2022/02/study-of-gas-laws-class-9-chemistry.html Chapter 8 Atmospheric Pollution:  http://novakid...

Selina ICSE Solutions for Class 9 Chemistry Chapter 8 Atmospheric Pollution Page No: 128 Question 1. Define the following terms: pollution pollutant air pollution Solution: Pollution may be defined as contamination of air, water or soil by undesirable amounts of materials or heat and is caused by the concentration of substances which have harmful effects. Toxic and otherwise harmful substances which have an undesirable impact on different components of the environment and life forms are known as pollutants. Air pollution means degradation of air quality due to concentration of harmful contaminants which affect human, plant and animal lives. Question 2. Name any four gaseous pollutants. Solution: Sulphur dioxide, hydrogen sulphide, carbon monoxide and hydrocarbons. Question 3. Name the compounds of sulphur that cause air pollution. Also state the harmful effects of sulphur compounds. Solution: Compounds of sulphur like sulphur dioxide, sulphur trioxide and hydrogen sulphide are pollutan...

Selina ICSE Solutions for Class 9 Chemistry Chapter 7 Study of Gas Laws Page No: 122 Question 1. What do you understand by gas? Solution: The state of matter in which inter-particle attraction is weak and inter-particle space is so large that the particles become completely free to move randomly in the entire available space, is known as gas. Question 2. Give the assumptions of the kinetic molecular theory. Solution: The main assumption of the kinetic molecular theory of gases are as follows: All gases are made up of a large number of extremely small particles called molecules. There are large vacant spaces between the molecules of a gas so that actual volume of the molecules of a gas is negligible as compared to the total volume occupied by the gas. The molecules of a gas are always in a state of constant random motion in straight lines in all possible direction. There are negligible attractive forces between the molecules of a gas. There is no effect of gravity on the motion of the m...