EDUCATRIX

CHEMICAL EFFECTS OF ELECTRIC CURRENT ELECTRIC CURRENT The rate of flow of charges is known as electric current. CLASSIFICATION OF MATERIALS BASED ON CONDUCTIVITY Materials are classified into three based on their conductivity:- conductors, semiconductors and insulators Materials that allow current to pass through them are called conductors Materials that do not allow current to pass through them are called insulators Materials which have a conductivity between conductors and insulators are called semiconductors CONDUCTIVITY OF LIQUID  The conductivity of a liquid is based on the presence of ions(charged particles) in it. (in other words conductivity of the liquid is a measure of ions that are free to move) NOTES:- IONS are charged atoms. positively charged atoms are known as cations and negatively charged atoms are known as cations  DIAGRAMMATIC REPRESENTATION OF ELECTRIC CURRENT THROUGH LIQUID  The positive electrode is known as the anode and the negative electrode is kn...

COMBUSTION AND FLAME  The burning  of any substance is considered a chemical change because a new substance is produced along with the change in the chemical structure. (burning means reacting with oxygen) eg:- burning of magnesium ribbon (where magnesium is converted to magnesium oxide) COMBUSTION A chemical process in which a substance reacts with oxygen to produce heat energy is called combustion. During combustion carbon-di-oxide and water is also produced ie, substance burn + oxygen -----> carbon-di-oxide+ water + heat/light energy A substance that undergoes combustion is said to be combustible and it is also known as fuel eg:-wood, paper, petrol, kerosene, diesel etc  A substance which does not undergo combustion is said to be non-combustible. eg:- iron nail, stone, glass etc NOTE:- Oxygen gas is necessary for the combustion reaction. If oxygen supply is not there means burning doesn't happen or if oxygen supply is insufficient means it will result in the product...

COAL AND PETROLEUM    NATURAL RESOURCES AND MAN MADE RESOURCES Resources which are available in the nature and can used without modification for human needs is known as natural resources. eg:-air, water, sunlight Resources created by the human beings are called man made resources. eg:-petrol, LPG, CNG CLASSIFICATION OF NATURAL RESOURCES Resources that are present in unlimited quantity in nature and are not likely to be exhausted by human activities is called  INEXHAUSTIBLE NATURAL RESOURCES The amount of some resources in the nature is limited. then can be exhausted by human activities is called  EXHAUSTIBLE NATURAL RESOURCES FOSSIL FUELS Some exhaustible natural resources such as coal, petroleum, natural gas etc. are formed from the dead remains of living organisms(fossil). So these resources are called fossil fuels  DIFFERENT TYPES OF FOSSILE FULES COAL Due to natural process like flood forests in the low laying areas got buried under the soil as they sank dee...

 MATERIALS METALS AND NON METALS Materials around us can be classified as  metals and non-metals  based on their physical  and chemical properties  (Note:- Materials which show intermediate properties of metals and nonmetals are known as metalloids Eg:- boron, silicon, germanium) PHYSICAL PROPERTIES OF METALS  1)LUSTRE Lustrous means something that shines. Metallic lustre is a property of the metal to have a shining surface (All the metals have lustre property. Gold platinum and silver are comparatively more lustrous than other metals) 2) HARDNESS Generally, metals have high density and they are solid at room temperature so they are hard it is not easy to break or change  the shape of metals  (Most of the metals are hard but sodium and potassium are soft metals that can be cut with a knife ) 3)MALLEABILITY  The property of metal by which it can be beaten into thin sheets is called malleability  (Aluminum foil used to wrap food material i...

 SYNTHETIC FIBRES AND PLASTICS SYNTHETIC FIBERS  Synthetic fibers are man-made fibers prepared from a chemical substance such as petrochemicals, so they are also known as man-made fibers. Synthetic fibers are generally polymers(polymers are the large single unit (large molecules) formed by joining repeated small unit( monomer) as a chain) TYPES OF SYNTHETIC FIBERS RAYON     Rayon is a synthetic fiber obtained from the chemical treatment of wood pulps. It is also known as artificial silks because its property is similar to that of silk.  PROPERTIES AND USES It is cheaper than silk and can be woven like silk fabric it can be dyed in various colours it can be mixed with cotton to make bedsheets it can be mixed with wool to make carpets NYLON Nylon is a man made fiber prepared from coal, water and air. It was the first fully synthetic fiber PROPERTIES AND USES it is strong, elastic, light, lustrous and easy to wash, so it is used widely to make cloths it is used to ...

There are many objects of diverse nature around us, which is made up of different type of particles  eg;  rocks, milk, air etc PROPERTIES OF MATERIALS 1) All the  materials occupy their own space  2) All the materials around us have mass (mass is the quantity of substance present in an object) In general, all the materials around us can be called MATTER WHAT IS A MATTER? Anything that can occupy space and have mass is known as matter  PHYSICAL NATURE OF MATTER  * Matter is made up of particles  * Particles of matter are very very small (can’t see with our naked eyes)

Magnets are substances which can attract some materials like iron, steel, nickel etc.  Different types of magnets  Based on shape of the magnets we can classify magnets into different names. Pictures and names of som magnets are given below                   A magnet always has 2 poles a north pole and a south pole ( when a magnet is cut into two pieces, the new pieces formed will act as separate magnets with a north pole and south pole for each