Matter Class-8th Goyal Brothers ICSE Chemistry Solutions Ch-1

Matter Class-8th Goyal Brothers ICSE Chemistry Solutions Ch-1 Unit 1 . We Provide Step by Step Answers of Objectives,  True and False, Incorrect and Correct , Definitions , Match the followings and Short/Long Question Type answers of Chapter-1, Unit 1, Matter. Visit official Website  CISCE  for detail information about ICSE Board Class-8

Matter Class-8th Goyal Brothers ICSE Chemistry Solutions Ch-1

Board ICSE
Class 8th
Subject Chemistry
Book Name Goyal Brothers
Chapter-1 Matter
Unit-1 Matter
Topic Solution of exercise questions
Session 2023-24

Matter Class-8th Goyal Brothers ICSE Chemistry Solutions Ch-1

OBJECTIVE TYPE QUESTIONS

A. Fill in the blank spaces by choosing the correct words from the given list :

List : free, mass, vibrate, increases, molecules.

  1.  The quantity of matter present in an object is called ….mass…. .
  2. All matter is composed of small particles called ….molecules… .
  3. The force of attraction between the particles decreases, if the distance between them …increases… and vice versa.
  4. The molecules of the solids can just …vibrate… about their mean positions.
  5. The molecules of a liquid are …free… to move about within the liquid.
B. Statements given below are incorrect. Write the correct statements.

1. Solids have only one free surface.

Correct – Solids have only six free surface.

2.The molecules of a gas generally move in any one direction.

Correct – The molecules of a gas generally move in all direction.

3.The various state of matter can be interchanged into one another by altering the conditions              of volume.

Correct – The various state of matter can be interchanged into one another by altering the conditions of temperature.

4.The process due to which liquid changes into gaseous state by absorbing heat energy at         certain temperature is called evaporation.

Correct – The process due to which liquid changes into gaseous state by absorbing heat energy at   certain temperature is called boiling.

5. By sublimation of air, we can separate oxygen and nitrogen gases.

Correct – By purification of air, we can separate oxygen and nitrogen gases.

C. Match the statements in Column A, with those in Column B.
                                                 Column A        Column B
1. The intermolecular force acting between same kind of molecules. (a)Melting
2. The intermolecular force acting between different kinds of molecules. (b)Cohesive
3. Intermixing of different substances due to random motions of their molecules. (c) Gas
4. The molecules of a state of matter having very large kinetic energy. (d)Adhesive
5. The process due to which a solid changes into liquid state by absorbing of heat energy. (e)Diffusion

Answer :

                                         Column A        Column B
1. The intermolecular force acting between same kind of molecules. (a)Cohesive
2. The intermolecular force acting between different kinds of molecules. (b)Adhesive
3. Intermixing of different substances due to random motions of their molecules. (c)Diffusion
4. The molecules of a state of matter having very large kinetic energy. (d) Gas
5. The process due to which a solid changes into liquid state by absorbing of heat energy. (e) Melting       
D. Write ‘true’ or ‘false’ for the following statements :
                                             Statement        True/False
1. Solids do not diffuse when they are kept in contact with one another.
2. The density of liquids is relatively more than solids.
3. Gases expand to a large extant when heated.
4. In case of boiling, the liquids can slowly change into gaseous form at a temperature below their boiling point.
5. The mass can neither be created nor destroyed.        

     Answer :      

                                             Statement        True/False
1. Solids do not diffuse when they are kept in contact with one another.          T
2. The density of liquids is relatively more than solids.          F
3. Gases expand to a large extant when heated.          T
4. In case of boiling, the liquids can slowly change into gaseous form at a temperature below their boiling point.          F
5. The mass can neither be created nor destroyed.          T    
E. Tick (√) the most appropriate answer.

1. With the supply of heat energy to matter, the kinetic energy of its particles :

(a) decreases                                             (b) increases

(c) remains same                                      (d) cannot be said

Answer : option (b) increases is correct

2. Which of the following state of matter is highly compressible ?

(a) Solid                                                     (b) Liquid

(c) Gas                                                       (d) None of these

Answer : option (c) Gas is correct

3. The various state of matter can be interchanged into one another by altering the conditions of :

(a) pressure                                               (b) temperature

(c) volume                                                  (d) both (a) and (b)

Answer : option (d) both (a) and (b) is correct

4. The process due to which a liquid changes into solid state by giving out heat energy, is called

(a) melting                                                   (b) freezing

(c) boiling                                                     (d) evaporating

Answer : option (b) freezing is correct

5. The process due to which a solid directly changes into gaseous state on heating, without changing first into the liquid state, and the gaseous state on cooling directly changes into solid state, without changing first into the liquid state, is called

(a) condensation                                        (b) fusion

(c) freezing                                                  (d) sublimation

Answer : option (d) sublimation is correct

STUDY QUESTIONS

Matter Class-8th Goyal Brothers ICSE Chemistry Solutions Ch-1 Unit 1

1. Define matter. State three characteristics of matter. Can light be classified as matter ? Give one reason.

Answer :  Light can’t be classified as matter as it doesn’t cope up with definition nor matter’s characteristics.

2. Bring out clearly the difference between following by giving examples :

(a) Material and substance

Answer : A substance is a form of matter that has a uniform properties while a material is a matter from which a thing is or can be made.

For example, Pure solids, liquids and gases etc. are substances. And Wood, Book, Table, Stone, Fibers, etc. are materials.

(b) Homogeneous material and heterogeneous material.

Answer : A homogeneous mixture has the same uniform appearance while heterogeneous mixture consists of visibly different substances.

For example, Air, Most Alloys, etc. are example of homogeneous And heterogeneous include Sand and oil in water, Toy box filled with toys, etc.

3. Define the terms given below and answer the questions associated to each term.

(a) Solid : Why do solids not diffuse in one another ?

Answer : The particles must be able to move around for diffusion to work. Diffusion does not occur in solids because the particles in a solid can only vibrate and cannot migrate from one location to another.

(b) Liquid : Why do liquid flow ?

Answer : Liquids flow because the particles in a liquid are not very tightly bound to each other and they have high intermolecular spaces between them, which allows the particles to be displaced or move causing the liquids to flow.

(c) Gas : Why are gases highly compressible ?

Answer : Gases are highly compressible because they have large intermolecular spaces between the molecules. As a result, its intermolecular force of attraction is very weak Therefore, gases are easily compressible.

4. Name the change of state during the following changes :

(a) Formation of clouds.

Answer : Formation of clouds – gas to solid or liquid.

(b) Drying of wet clothes.

Answer : Drying of cloths – evaporation (from liquid to gas as vapor)

(c) Naphthalene balls become smaller when kept in air.

Answer :  Naphthalene balls become smaller when kept in air- it changes from solid to directly gas.

(d) Formation of snow.

Answer : Formation of snow- liquid to solid and evaporation of water – liquid to gas

(e) Melting of wax when kept in sunshine.

Answer : Melting of wax in sunshine – melting( from solid to liquid)

5. List the main postulates of kinetic theory of matter.

Answer : The main postulates of the kinetic molecular theory of matter are as follows:

  • The particles in a gas are in constant, random motion.
  • The combined volume of the particles is negligible.
  • The particles exert no forces on one another.
  • Any collisions between the particles are completely elastic.
  • The average kinetic energy of the particles is proportional to the temperature in kelvins.
6. State whether the statements given below are true or false :

(a) Gases have any number of free surface. [F]

(b) Intermolecular force in case of solids is maximum. [T]

(c) During sublimation, the substance must be heated. [T]

(d) A decrease in pressure lowers the boiling point of liquid. [T]

(e) During interconversion of matter, mass remains constant. [T]

(f) Molecules of gas have least kinetic energy. [F]

(g) During freezing the temperature continues to fall. [F]

(h) Liquids have only one free surface. [T]

7. (a) State the law of conservation of mass.

Answer : The law of conservation of mass states that. “The mass in an isolated system can neither be created nor be destroyed but can be transformed from one form to another”. According to the law of conservation of mass, the mass of the reactants must be equal to the mass of the products for a low energy thermodynamic process.

(b) How can you verify this law using barium chloride and sodium sulphate solution ?

Answer : Thus, we can say that the law of conservation of mass is preserved.
Therefore, we can see that Barium Chloride reacts with Sodium Sulphate to form Barium Sulphate and Sodium Chloride, which according to the law of conservation of mass, proves that the total mass of the reactants is equal to the total mass of products.

— : end of Matter Class-8th Goyal Brothers Answers :–

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