A substance which is made up of only one kind of particles or molecules are known as pure substance
A substance which cannot be split up into two or more substance by using chemical method of applying heat, light or electric energy is known as Elements eg. Sodium , Hydrogen etc.
There are 118 elements found till now, out of these 92 are occur in nature and rest are artificially prepared. Everything in the world is made up of one or more elements. These can be solid , liquid or gas. Mercury and Bromine are only two elements which are liquid at room temperature. Elements are divided into three groups:
- Non metals
Elements which have tendency to conduct electricity and they are malleable and ductile are known as metals eg. Iron, Zinc, silver etc. Metals have high tensile strength. They tends to loose electrons in chemical reaction
Elements which have not tendency to conduct electricity are known as non metals. They are neither ductile nor malleable. eg. Carbon, sulphur, Bromine etc. Bromine is only non metal which is liquid at room temperature. Non metals tends to gain electron in chemical reaction
There are few elements which show some properties of metals and other properties of non metals. They are also called semi metals. eg. Boron, Silicon, Germanium, Arsenic, Antimony, Tellurium and Astatine are Metalloids.
Metalloids have their unique conductivity property which make them valuable in the semiconductor and computer chip industry.
A substance which are made up of two different compound without combined chemically. A mixture can be separate by physical process like Sublimation, Evaporation, Filtration, Distillation etc. eg. Air is a mixture of many gases.
Mixture is of two type
- Homogeneous mixture: Mixture in which the substance are not separated by any method. All homogeneous mixture are called solutions. eg. Sugar solutions, Salt solutions etc.
- Heterogeneous mixture: Those mixture in which the substance remain separate and one substance is spread throughout the other substance. eg. Sugar and Salt mixture, Water and Sand mixture etc.
It is a substance which is made up of two or more elements which are chemically combined in a fixed portion of mass. It cannot be separated into its parents elements by physical process. The property of compound is different from its parents elements. In compound there is energy absorbed or released during preparation of it. eg. carbon dioxide, water etc
It is a homogeneous mixture of two or more substance. The mixture which is dissolved to make solutions is called solute and in which solute is dissolved is called solvent. Size of solute particles less then 1 nm. eg. Salt solutions, Sugar solutions etc
It is a heterogeneous mixture have quite large solute particles. The particles do not pass through a filter paper. So it can be separated by filtration. eg. Chalk water mixture, Muddy water etc.
It is a kind of solutions in which size of particles is between solutions and suspension. They appear to be homogeneous but in reality it is heterogeneous. eg. Jelly, Milk etc.
Separation of Mixture
- Separation of mixture of two solids:
- Separation by suitable solvent: One element of a mixture is soluble in a particular liquid solvent whereas other is insoluble in it. This difference is used for separation. For eg. sugar is soluble in water where as sand is insoluble
- Separation by magnet: This property of iron is used to separate from a mixture. for eg. Mixture of iron filings and sulphur powder.
- Separation of mixture of a solid and a liquid:
- By Filtration: It is used for separating insoluble substance from liquid. The liquid passes through the filter paper where as solid particles doesn't pass.
- Separation by Evaporation: It is used for separate a solid substance that has dissolved in liquid. We evaporate the liquid and after that we get solid particles which is dissolved in liquid.
- Distillation: It is a process of heating a liquid to form vapour and then cooling the vapour to get back liquid.
- Separation of mixture of two (or more) Liquids:
- By fractional distillation: It is a process in which two miscible Liquids are separating by distillation, the one liquid being collected in fraction boiling at different temperature. eg. Petrol and LPG
- Separation funnel: A mixture of two liquid can be separated by using funnel. It is a special type of funnel which has a stop cock in its stem allows the flow of liquid from it or stop the flow of liquid from it. The separation depends on the density of fluid. eg. Water and Kerosene