{"id":152750,"date":"2023-12-28T14:54:26","date_gmt":"2023-12-28T09:24:26","guid":{"rendered":"https:\/\/icsesolutions.com\/?p=152750"},"modified":"2023-12-29T10:09:40","modified_gmt":"2023-12-29T04:39:40","slug":"living-science-chemistry-class-8-icse-solutions-chapter-1","status":"publish","type":"post","link":"https:\/\/icsesolutions.com\/living-science-chemistry-class-8-icse-solutions-chapter-1\/","title":{"rendered":"Living Science Chemistry Class 8 ICSE Solutions Chapter 1 Matter"},"content":{"rendered":"

ICSE Living Science Chemistry for Class 8 Solutions Chapter 1 Matter<\/h2>\n

Think And Answer (Page 4)<\/span><\/p>\n

Question 1.
\nWhen water is cooled, it changes to ice. Why?
\nAnswer:
\nWhen the temperature is decreased, the molecules of a water lose kinetic energy gradually and slow down. As a result, the intermolecular force of attraction between them increases and ‘ the molecules come close together. With continued cooling, the intermolecular space decreases to such an extent that water changes to a solid ice.<\/p>\n

Question 2.
\nA gas completely fills the container in which it is kept. Why?
\nAnswer:
\nThe intermolecular force of attraction is the weakest in gases. , So, the intermolecular space in gases is the largest in comparison to liquids and solids. As a result, the molecules in gases are very far apart and randomly move about in the whole space available to them.<\/p>\n

Check Your Progress (Page 7)<\/span><\/p>\n

Write true or false. Correct the false statements
\nQuestion 1.
\nMolecules in motion possess energy called kinetic energy.
\nAnswer:
\nTrue.<\/p>\n

Question 2.
\nThe filled-up spaces between the different molecules are called the intermolecular spaces.
\nAnswer:
\nTrue.<\/p>\n

Question 3.
\nThe force of attraction between molecules of a substance is called the intermolecular force of attraction.
\nAnswer:
\nTrue.<\/p>\n

Question 4.
\nThe intermolecular force of attraction in liquids is as strong as that in solids.
\nAnswer:
\nFalse. The intermolecular force of attraction in solids is stronger as that in liquids.<\/p>\n

Question 5.
\nThe molecules in gases frequently collide with each other and the sides of the container in which they are kept.
\nAnswer:
\nTrue.<\/p>\n

A. Tick the most appropriate answer.<\/span><\/p>\n

1. In which of the following is the intermolecular space between molecules the least?
\na. solids
\nb. liquids
\nc. gases
\nd. none of these
\nAnswer:
\na. solids<\/p>\n

Question 2.
\nWhat happens to the intermolecular force of attraction as the intermolecular space between molecules decreases?
\na. It decreases.
\nb. It increases.
\nc. It does not change.
\nd. It may increase or decrease.
\nAnswer:
\nb. It increases.<\/p>\n

Question 3.
\nIn which of the following is the intermolecular force the weakest?
\na. solids
\nb. liquids
\nc. gases
\nd. none of these
\nAnswer:
\nc. gases<\/p>\n

Question 4.
\nWhich form of energy do the molecules of a substance gain when it is heated?
\na. electrical
\nb. chemical
\nc. water
\nd. kinetic
\nAnswer:
\nd. kinetic<\/p>\n

Question 5.
\nWhich of the following statements is false with respect to the law of conservation of mass?
\na. Matter is neither created nor destroyed during a chemical reaction.
\nb. There is no change is mass during a chemical reaction.
\nc. The mass of the products equals the mass of the reactants in a chemical reaction.
\nd. There is a change in mass during a chemical reaction,
\nAnswer:
\nd. There is a change in mass during a chemical reaction.<\/p>\n

B. Fill in the blanks.
\n<\/span><\/p>\n

Question 1.
\nThe empty spaces between different molecules are called ……….. or ……….. spaces.
\nAnswer:
\nThe empty spaces between different molecules are called inter-particle or intermolecular spaces.<\/p>\n

Question 2.
\nThe force of attraction between molecules of the same kind is called ………..
\nAnswer:
\nThe force of attraction between molecules of the same kind is called cohesive.<\/p>\n

Question 3.
\nThe force of attraction between molecules of different kinds is. called ………..
\nAnswer:
\nThe force of attraction between molecules of different kinds is called adhesive.<\/p>\n

Question 4.
\nThe collisions between the molecules and container exert ……….. on the walls of the container.
\nAnswer:
\nThe collisions between the molecules and container exert pressure on the walls of the container.<\/p>\n

Question 5.
\nWhen a solid is heated, its molecules gain ……….. energy.
\nAnswer:
\nWhen a solid is heated, its molecules gain kinetic energy.<\/p>\n

Question 6.
\nMatter is neither ……….. nor ……….. during a chemical reaction.
\nAnswer:
\nMatter is neither created nor destroyed during a chemical reaction.<\/p>\n

C. Write true or false. Correct the false statements.
\n<\/span><\/p>\n

Question 1.
\nThe molecules of a substance collide with each other.
\nAnswer:
\nTrue<\/p>\n

Question 2.
\nIn solids, molecules move randomly.
\nAnswer:
\nFalse; In gases molecules move randomly.<\/p>\n

Question 3.
\nAs the temperature of a substance increases, its molecules move faster and thus the kinetic energy of the molecules increases.
\nAnswer:
\nTrue<\/p>\n

Question 4.
\nThe intermolecular force of attraction in liquids is not as strong as that in solids.
\nAnswer:
\nTrue<\/p>\n

Question 5.
\nThe intermolecular force of attraction is the strongest in gases.
\nAnswer:
\nFalse; The intermolecular force of attraction is the strongest in solids.<\/p>\n

Question 6.
\nWhen a solid is heated, its molecules lose kinetic energy and become very active.
\nAnswer:
\nFalse; When a solid is heated, its molecules gain kinetic energy and become very active.<\/p>\n

D. Match the columns.<\/span><\/p>\n

\"ICSE
\nAnswer:
\n\"ICSE<\/p>\n

E. Name the following.
\n<\/span><\/p>\n

Question 1.
\nThe energy possessed by molecules in motion.
\nAnswer:
\nKinetic energy<\/p>\n

Question 2.
\nThe theory that enables us to understand the behaviour of molecules of solids, liquids and gases.
\nAnswer:
\nKinetic theory of matter<\/p>\n

Question 3.
\nThe empty spaces between different molecules.
\nAnswer:
\nInter-particle or intermolecular space<\/p>\n

Question 4.
\nThe attractive forces between the molecules of a substance.
\nAnswer:
\nInter-particle or intermolecular force of attraction<\/p>\n

Question 5.
\nThe law that states that the mass of the products equals the mass of the reactants in a chemical reaction.
\nAnswer:
\nLaw of conservation of mass<\/p>\n

F. Answer the following in short.
\n<\/span><\/p>\n

Question 1.
\nWhat are the empty spaces between the different molecules of matter called?
\nAnswer:
\nThe empty spaces between different molecules are called interparticle or intermolecular spaces.<\/p>\n

Question 2.
\nWhat is the force of attraction between the molecules of a substance called?
\nAnswer:
\nThe force of attraction between the molecules is called inter\u00acparticle or intermolecular force of attraction.<\/p>\n

Question 3.
\nWhat is cohesive force?
\nAnswer:
\nThe force of attraction between the molecules of the same kind is called cohesive force.<\/p>\n

Question 4.
\nWhat is adhesive force?
\nAnswer:
\nThe force of attraction between the molecules of different kinds is called adhesive force.<\/p>\n

Question 5.
\nWhen a solid is heated, what happens to its molecules?
\nAnswer:
\nWhen a solid is heated, its molecules gain kinetic energy and become very active.<\/p>\n

Question 6.
\nWhen a gas is cooled, what happens to its molecules?
\nAnswer:
\nSimilarly, when the temperature is decreased, the molecules of a substance lose kinetic energy gradually and slow down.<\/p>\n

G. Answer the following in detail.<\/span><\/p>\n

Question 1.
\nList the main postulates of the kinetic molecular theory of matter.
\nAnswer:
\nThe main postulates of the kinetic molecular theory of matter are as follows.
\n1. Composition of matter: Matter is composed of molecules. The molecules of a given substance are identical in all respects.<\/p>\n

2. Movement of molecules and kinetic energy : Molecules in matter move constantly. Due to this movement, molecules possess energy called kinetic energy.<\/p>\n

3. Intermolecular space : There are empty spaces between the molecules of matter. The empty spaces between different molecules are called inter-particle or intermolecular spaces. The intermolecular space between the molecules in gases is the largest.<\/p>\n

4. Intermolecular force of attraction : There are attractive forces between the molecules of a substance. The force of attraction between molecules is called inter-particle or intermolecular force of attraction. The intermolecular force of attraction between , the molecules in solids is the largest<\/p>\n

5. Collision of molecules : The molecules of a substance collide with each other. In the gaseous and liquid states, the molecules also collide with the walls of the container in which the substance is kept. The collisions between the molecules and the container exert pressure on the walls of the container.<\/p>\n

6. Movement of molecules in different states : The molecules of matter are in motion. In solids, they only vibrate. In liquids and gases, they move randomly and thus possess kinetic eneigy.<\/p>\n

Question 2.
\nDifferentiate between cohesive force and adhesive force.
\nAnswer:
\nThe force of attraction between the molecules of the same kind is called cohesive force. The force of attraction between the molecules of different kinds is called adhesive force.<\/p>\n

Question 3.
\nExplain the nature of molecules in solids, liquids and gases.
\nAnswer:
\nThe molecules in solids hardly move about; they only vibrate about their positions. The molecules in liquids collide more frequently with each other than in gases due to shorter distances between them. The molecules in gases also frequently collide with each other and with the sides of the container in which they are kept.<\/p>\n

Question 4.
\nExplain the change of state of matter on cooling.
\nAnswer:
\nSimilarly, when the temperature is decreased, the molecules of a substance lose kinetic energy gradually and slow down. As a result, the intermolecular force of attraction between them increases, and the molecules come close together. With continued cooling, the intermolecular space decreases to such an extent that a gas changes to a liquid and a liquid changes to a solid.<\/p>\n

Question 5.
\nExplain the law of conservation of mass with an example.
\nAnswer:
\nThe law of conservation of mass states that matter is neither created nor destroyed during a chemical reaction. In a chemical reaction, a change in the composition of substances occurs, but there is no overall change in mass.
\nFor example, as magnesium burns in oxygen to produce magnesium oxide, the total mass of the oxygen and magnesium reacted, equals the mass of the magnesium oxide produced.
\nmagnesium + oxygen \u2192 magnesium oxide
\nmass before the reaction = mass after the reaction<\/p>\n

H. Complete these word equations.<\/span><\/p>\n

1. magnesium + …………. \u2192 magnesium oxide
\nAnswer:
\nmagnesium + oxygen \u2192 magnesium oxide<\/p>\n

2. …………. + hydrogen \u21cc ammonia
\nAnswer:
\nnitrogen + hydrogen \u21cc ammonia<\/p>\n

3. barium chloride + sodium sulphate \u2192 ……….. + ………..
\nAnswer:
\nbarium chloride + sodium sulphate \u2192 barium sulphate (white precipitate) + sodium chloride<\/p>\n

Living Science Chemistry Class 8 ICSE Solutions<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

ICSE Living Science Chemistry for Class 8 Solutions Chapter 1 Matter Think And Answer (Page 4) Question 1. When water is cooled, it changes to ice. Why? Answer: When the temperature is decreased, the molecules of a water lose kinetic energy gradually and slow down. As a result, the intermolecular force of attraction between them …<\/p>\n","protected":false},"author":8,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"spay_email":""},"categories":[3034],"tags":[],"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/icsesolutions.com\/wp-json\/wp\/v2\/posts\/152750"}],"collection":[{"href":"https:\/\/icsesolutions.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/icsesolutions.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/icsesolutions.com\/wp-json\/wp\/v2\/users\/8"}],"replies":[{"embeddable":true,"href":"https:\/\/icsesolutions.com\/wp-json\/wp\/v2\/comments?post=152750"}],"version-history":[{"count":1,"href":"https:\/\/icsesolutions.com\/wp-json\/wp\/v2\/posts\/152750\/revisions"}],"predecessor-version":[{"id":165232,"href":"https:\/\/icsesolutions.com\/wp-json\/wp\/v2\/posts\/152750\/revisions\/165232"}],"wp:attachment":[{"href":"https:\/\/icsesolutions.com\/wp-json\/wp\/v2\/media?parent=152750"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/icsesolutions.com\/wp-json\/wp\/v2\/categories?post=152750"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/icsesolutions.com\/wp-json\/wp\/v2\/tags?post=152750"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}