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Separation of Substances (Pure Substances and Mixtures) Sand - Mixture Sand - Mixture Water - Pure SubstanceA pure Substance consists of only one kind of particles.A mixture consists of two or more kind of particles.
Types of MixtureA homogeneous mixture is that which has the same composition throughout, that is, itscomponents are uniformly distributed and cannot be distinguished from each other.A heterogeneous mixture is that which does not have the same compositionthroughout, that is, its components are not uniformly distributed and can bedistinguished from each other
Separating the components of Mixtures a. Mixture of Solids with Solids i. Hand PickingThe components of a solid-solid mixture can be separated by hand picking. Fore.g. separating pebbles from rice or dal, separating grass from mint leaves.
ii. Threshing This method is generally used by the farmers to separate the grains from the stalks after harvesting. The dried stalks are beaten or threshed to separate the grains. However, in large farms threshing is done by using threshing machines.
iii. Winnowing WinnowingIn this method, the mixture is allowed to fall from a height. The lighten components get separated from the heavier ones because of wind or air blow. This method is used to separate lighter husk from heavierGrains like wheat.
iv. SievingThis method is used to separate the components that are of different sizes. For sieving, asieve is used.Sieve is a wire mesh fixed tightly in a frame.
v. Magnetic SeparationIn this magnetic substances (like iron get attracted by the magnet. For e.g.- when amagnet is brought near iron pins, all pins get clinged to it.
vi. SublimationThe process in whicha solid changesdirectly into gaseousstate on heating iscalled sublimation.
b. Mixture of solids with liquidsi. EvaporationEvaporation is a process in which a liquid changesinto gaseous form on heating is called evaporation.
ii. CrystallizationCrystallization is a process which separates a pure solid inthe form of its crystals from a saturated solution.
2. Separating solids that do not dissolve in liquids i. Sedimentation and DecantationSedimentation is the process by which the insoluble, heavy solid particles settle downtheir own in a solution. In order to separate the two, the liquid has to be gently pouredinto another container without disturbing the sediments. This process of obtaining clearliquid by pouring it into another container without disturbing the sediments is calleddecantation.
ii. Loading Loading is a process which speeds up the sedimentation. In fact, loading is a faster process as compared to sedimentation.
iii. Filtration Filtration is a process of separating insoluble solids (like mud, tea leaves etc.) from a liquid using fine pores of the filter.
Separating immiscible liquidsIt is a mixture of two liquids which do not mix with each other.
MADE BY: RITISHA SINGHCLASS: 6 C thROLL NO: 27