Is Matter Around Us Pure? - PDF

1s Matter Around Us-p -.. ,. "re1 di...

1s Matter Around Us-p -.. ,. "re1 di "The nature of matter, or body consider... ed in consists not in ,ts being something which ,s h 9e,,~ ard · + Matter or coloured or which affects the senses m o, heii '. any w '1 + Pure Substances : Elements and simply in its being something which is extend. aY. L ed in ~ Compounds breadth and depth". fe,,911 + Impure Substances : Mixture - Rene Des + Ca\ What is a Solution? When we look around, we can see different type. S Of Ill + Heterogeneous Mixture like milk, fog, smoke, ghee, Juices etc. How d a~ o We~ + Physical and Chemical Changes that these things are pure For a scientist Pur e actw 11 + Quick Recap means that 1t contains only one type of matter O a~ r Par1Jr1._ But all the matter around us 1s not pure, intact th "'tl + Assignment ' ey are two types : ~ ✓Pure substances l ii} Mixtures Let us now discuss these two in a little more detail. MATTER Matter Pure aubstancu Impure aubstanca1 (Mlxtu,..J (Ftxed composlbon) (No fixed composdJOn) I I l l Elements Compc,unds Homogenous H1tor~ ! ! mixtures mlmHIS Cannot be broken down Have fixed compos1bon. Uniform composition Non-undorm i i rnto simpler substances l Can be broken down Into lhroughout rts mass elements by chemical or g sugar rn water electn)chem,cal reachon salt in water. water rn compolllDI eg sanda water walsrn e g water. methane alcohol, sulphur 1n ooleic. Metals Non-metals metalloods sugar, salt etc · carbon d1sulph1de + + + etc (True solutJons) eg eg eg Gold. Hydrogen Boron Suspension Colloids Silver. Oxygen, Sdtcon, e g Sand rn water e g Slardl soUat Mercury. Iodine, Germanium Iron. Sodium. Carbon etc etc Potassium etc ~ NawDelha-110005, Ph.011-47623456  1 x,n 111 I I MI rN Ill M Nl N :11' 1 I) wh1c.il h.is 011ly O f OM 11I no or amo ~I d of umtan OO X c: 16.67 g So, the mass of water that should be evaporated = 16 67 g [Exam_p_le_ S_:_ _ _ _ ;:::=-:-7:-==::-::-:::--:--:-::------:----- -_ If 2 mL of acetone is present in 45 ml of its aqueous solution then c l of this solution by volume percentage method. ' a cu/ate the Con Solution:. ~ This solution contains a liquid solute (acetone) mixed with a liquid solvent an aqueous solution), so Water {bee;i \ Concentration of solution = Volume of solute x 100 Volume of solution Volume of solute = 2 ml Volume of solution =Volume of solute + volume of solvent =45 ml So, concentration of solution = _3__ x 100 = 4.4% 45 Thus, the concentration of this acetone solution is 4.4%. HETEROGENEOUS MIXTURE Heterogeneous mixture is of two types : ~ (1) Suseeosjon (A suspension is a hetem_geneous mixture in which the small particles of spread throughout tfie solvent without dissolving in it. a SO!ut~~ The size of solute particles in a suspension is greater than 1~ m. Some examples of suspension are : Chalk-water mixture, muddy-water, sand particles suspended in water. Solid particles and remain separate in a suspension. 111 - Suspensions are formed by substances which do not dissolve in water. Characteristics of Suspensions- (i) A suspension is a heteroge11eous mixture. (ii) The size of solute particles in a suspension is large (greater than 10-' m) in diameter. (iii} The particles of a suspension can be seen by naked eyes easily ~ ~ : ~ h : f o w e r , 8, Puss Road, :!.:w Delhi-110005, Ph.011-47623456  Is Mnllor Around Us Pure'r. - ,,A ~u~pons1on cm be sopordtod by flitrollon Su pt'n-;1on~ uro unc;toblo 1,articlcs of suspension scattur ab k Its path visible earn of light passing through It and ma 8 but whon the particles settle down th t scatter 11ght any , e suspension breaks and it does no n,ore Ids , A colloid 1s a solution in h h t of a true :l cotIO w ich the size of solute particles 1s bigger than I a soiubon but smaller than that of a suspension Thus, colloids appear to be homogeneous but actually theY are heterogeneous when observed through a high-power microscope. so. colloids are not true solutions. Some examples of colloidal solutions are : starch solution, milk, blood, soap solution etc. 1nk. characteristics of Colloids (i) A colloid appears to be homogeneous but actually it is heterogeneous. yr The size of particles in a colloid is bigger than those m a true solution but smaller than th0se in a suspension. It is between 10-s m to 10-6 m (1 nm to 1000 nm) 111 diameter. ffe A colloidal solution cannot be separated by filtration through ordinary filter paper. (iv) Particles of a colloid do not settle down when left undisturbed, i e., a colloid 1s quite stable. (V) Colloids are big enough to scatter a beam of light passing through it. Note : A colloidal solution appears homogeneous but actually it is heterogeneous. Particle size Particle size Particle size less than between greater than 10.. m 10.. m to 1o'm 10-- m True solution Colloidal solution Suspensions Comparative sizes of particles in solutions Tyndall Effect : The scattering of light by colloidal particles is called Tyndall effect This effect 1s an optical property of colloids and can be used to distinguish a colloidal solution from a true $01Ution. Since the particles of a colloid distribute m a solvent non-uniformly, so the light rays show colhsion with these particles and get scattered. But the particles of a true solution are so small and homogeneously distributed that the light rays do not collide with them and hence, no scattering of l~ht rays takes place. Ca,porate Office: Aakash Tower, 8 Pusa Road, New Delhi-110005, Ph.011-47623456  MI r A1 u rl l I I l "'11 (for h 'I l Ii mplo Wh 1 , ,nllyht p t11ro11c1h t 111 py or lor ryndall ' ffo ' In nl t l p riltl of , fiord di pP. cr I In 1ir Tyndall effect A colloidal system conslsl5 of two phases Dispersed phase and D1spers1on mediun, Tha solute - like component or the dispersed particles ,n a colloid form the d1sp. 9 and the component ,n which the dispersed phase 1s present 1s known as dis ' a.d 1·.d ) Persio Collolds are classified according to the state (so l1 , 1qur or gas of the disp ersed n d1spers1on medium. ~h Dispersed phase (Discontinuous phase) : It is present 1n small amount similar to sO1Ute ~~n ~ Dispersion medium (Continuous phase) : It is present in large amount just like - aso11 solution ----- ®I 00 To further strengthen the concept of "Tyndall Effect", do check out this interesung 'It experiment video. To watch the video, scan the given QR code. Different Colloidal Compositions Gas Aerosol Fog, mist, clouds Solid Gas Aerosol Smoke dust, automobile exhaust Gas Liquid Foam Foams, whipped cream, shaving cream - Liquid Liquid Emulsion Milk, cod liver oil, ice-cream, face cream Solid Liquid Sol Starch sol, protein sol, gold sol, arsenious sulphide sol, milk of magnesia, mud Gas Solid Solid foam Foam, rubber, sponge, pumice - - ---+- Liquid Solid Gel Jelly, cheese, butter Solid Solid Solid sol Coloured gem stones, rock salt, milky glass Corporat~ l.ltrice: Aakash Tower, 8, Pusa Road, New Delhi-11 0005 Ph 011-47623456