IS MATTER AROUND US PURE
COMPOUNDS
A compound is a substance composed of two or more elements, chemically combined with one another in a fixed proportion. Compounds can be defined as substances consisting of 2 or more different types of elements in a fixed ratio of their atoms. When the elements combine, some individual property of the elements is lost and …
ELEMENTS
Robert Boyle was the first scientist to use the term element in 1661. Antoine Laurent Lavoisier (1743-94), a French chemist, was the first to establish an experimentally useful definition of an element. He defined an element as a basic form of matter that cannot be broken down into simpler substances by chemical reactions. Elements can …
Physical and Chemical
Changes
The properties that can be observed and specified like colour, hardness, rigidity, fluidity, density, melting point, boiling point etc. are the physical properites. The interconversion of states is a physical change because these changes occur without a change in composition and no change inthe chemical nature of the substance.Although ice, water and water vapour all …
In cities, drinking water purification from river water
In cities, drinking water is supplied from water works. A flow diagram of a typical water. From this figure write down the processes involved to get the supply of drinking water to your home from the water works .
HOW CAN WE OBTAIN PURE COPPER SULPHATE FROM AN IMPURE SAMPLE?
The crystallisation method is used to purify solids. For example, the salt we get from sea water can have many impurities in it. To remove these impurities, the process of crystallisation is used. Crystallisation is a process that separates a pure solid in the formof its crystals from a solution. Crystallisation technique is better than …
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HOW CAN WE OBTAIN DIFFERENT GASES FROM AIR ?
Air is a homogeneous mixture and can be separated into its components by fractionaldistillation. The flow diagram shows the following steps of the process. If we want oxygen gas from air , we have to separate out all the other gases present in the air. The air is compressed by increasing the pressure and is …
HOW CAN WE SEPARATE A MIXTURE OF TWO MISCIBLE LIQUIDS?
This method is called distillation. It is used for the separation of components of a mixture containing two miscible liquids that boilwithout decomposition and have sufficient difference in their boiling points. To separate a mixture of two or more miscible liquids for which the difference in boiling points is less than 25 K, fractional distillation …
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IS THE DYE IN BLACK INK A SINGLE COLOUR?
The ink that we use has water as the solvent and the dye is soluble in it. As the water rises on the filter paper it takes along with it the dye particles. Usually, a dye is a mixture of two or more colours. The coloured component that is more soluble in water, rises faster …
HOW CAN WE SEPARATE A MIXTURE OF SALT AND CAMPHOR?
camphor changes directly from solid to gaseous state on heating. So, to separate such mixtures that contain a sublimable volatile component from a non-sublimable impurity, the sublimation process is used . Some examples of solids which sublime are ammonium chloride,naphthalene and anthracene.