Question

Pure substances and mixture?

Answer 1

a Substance which is made up of the same kind of molecules is called a pure substances . it has definite characteristics properties . all elements and compounds are pure substances . for example , iron , copper , sugar , salt , water , oxygen , carbo dioxide , etc . are pure Substances..

a pure substances has its own sets of properties . these properties will be different for different substances . for example , the properties of sugar , such as taste , are different from those of common salt .

A pure substances has :-

( i ) same properties throughout it's bulk .

( ii ) fixed melting and boiling points , and .

( iii ) definite density .

a material obtained by mixing together two or more substances in any ratio which do not react with each other , is called a mixture . since a mixture has various components , it is an impure substance .

the varoius components in a mixture do not lose their properties . for example , sharbat is a mixture of sugar and water . sweetness of sugar and fluidity of water are present in sharbat .

types of mixture

mixture are classified according to how 'well mixed' they are , as homogeneous or heterogeneous .

heterogenous

a mixture in which components can be seen by naked eye or through magnifying glass is known as heterogenous mixture . it is the least ' well mixed ' of mixtures . the particles that made up the mixture are large enough to be seen . for this reason , they are easy to recognize and to separate from the mixture . A mixture of weat and barley , different sized button or different types of coins are example of a heterogenous mixture .

homogeneous

A mixture in which components cannot be seen by naked eye or through magnifying glass is known as homogeneous mixture , for example , sugar solution ( sugar and water ) , soda water ( carbon dioxide and water ) , air ( oxygen , nitrogen , carbon dioxide , water vapour ) , stainless steel, etc .

homogeneous mixture appear as if they contains only one substance . In fact , they contains several substances .