Lakhmir Singh Manjit Kaur Solution Class 6 Science Separation of Substances Exercise Solution (Very Short Type Questions, Short Type Questions, Long Answer Type Questions, MCQ Questions).
Pure Substances and Mixtures; Reasons for Separating Mixtures into Their Components : To Remove an Undesirable component or a Harmful component, To obtain pure sample of a Substance or a useful component; Methods of Separation of Mixtures : Threshing, Winnowing, Hand-Picking, Sieving, Magnetic-Separation, Decantation, Loading, Filtration, Evaporation and Distillation : Saturated Solutions ; Solubility; Effect of Heating and Coolong on a Saturated solution.
Chapter 5 – SEPARATION OF SUBSTANCES
Very Short Answer Type Questions
(1) Ans: Alum.
(2) Ans: Component of the mixture.
(3) Ans: Threshing.
(4) Ans: Hand picking.
(5) Ans: Sieving.
(6) Ans: Sieving.
(7) Ans: Magnetic separation.
(8) Ans: Electro magnets.
(9) Ans: Sieving.
(10) (a) The process of winnowing is used to remove small stone particles from wheat. – False
(b) A mixture of powdered salt and sugar can be separated by the process of winnowing. – False
(c) Grain and husk can be separated by the process of decantation. – False.
(d) Bran is separated from wheat flour by the hand picking method. – False
(e) Cream is separated from milk by sieving. – False
(f) A mixture of milk and water can be separated by filtration. – False
(g) Separation of sugar from tea can be done by filtration. – False
(h) Common salt is separated from its solution in water by decantation. – False
(11) Ans: Decantation
(12) Ans: Loading.
(13) Ans: Distillation
(14) Ans: A wire-mesh, a piece of cotton, a piece of muslin cloth, strainer.
(15) Ans: Evaporation.
(16) Ans: Distillation
(17) Ans: Evaporation.
(18) (a) to recover only salt?
(b) to recover salt as well as water?
(19) Ans: Saturated solutions.
(20) Fill in the following blanks with suitable words:
(a) Insect can be separated from wheat by hand picking.
(b) The method of separating seeds of paddy from stalks is called threshing.
(c) Salt is obtained from sea-water by the process of evaporation.
(d) The process of heating a liquid to form vapour, and then cooling the vapour to get back liquid is called distillation.
(e) When milk, cooled after boiling, is poured on to a piece cloth, cream is left behind on it. This process of separating cream from milk is an example of filtration.
(f) Impurities settled at the bottom when muddy water was kept overnight in a bucket. The process of separation used in this examples is called decantation.
Short Answer Type Questions
(21) Ans: The common salt dissolved in water can be separated by the process of evaporation.
- The process of evaporation is used on a large scale to obtain common salt from sea-water.
(22) Ans: Loading is the process in which alum particles are deposited on suspended clay particles of muddy water to make them heavy and settle down rapidly.
(23) Ans: The maximum amount of a substance which can be dissolved in 100 grams of water at a given temperature, is known as the solubility of that substance in water.
- The solubility of a substance in water increases on increasing the temperature.
(24) Ans: Fine sand is obtained by the method of sieving. The coars sand having larger particles and pebbles in it is put on a sieve consisting of a big iron mesh held in slanting position.
(25) Ans: At first we will take a glass full of water then we will put the mixture of mustard seeds and powdered common salt into the water.
we will mix it well and then powdered common salt will be dissolved and mustard seeds will be left.
(26) Ans: In factories, scrap iron is separated from the heap of waste materials by using big electromagnets fitted from the heap of wate materials by using big electromagnets fitted to a crane.
(27) (a) Ans: A cup of tea is a mixture of several components such as water, tea leaves extract, sugar and milk.
(b) Ans: The used tea-leaves are separated from prepared tea by the method of filtration.
(28) Ans: (a) Sedimentation: The deposition of solid matter at the bottom of a liquid is called sedimentation.
(b) Decantation: The pouring out of a liquid from a vessel without disturbing the sediment is called decantation.
(29) Ans: Warm water.
(30)Ans: In order to separate iron from sulphur, a horse-shoe type magnet is moved on the surface of the mixture. The iron filings are attracted by the magnet, they cling to the poles of the magnet and get separated.
(31) Ans: (a) Threshing: Threshing is the process in which stalks are beaten to separate grains from the stalks, and from the chaff that covers the grains.
(b) Winnowing: Winnowing is the method of separating husk grains with the help of wind.
(32) Ans: The method of winnowing is used to separate husk from various types of grains like wheat, rice, etc.
(b) Ans: The method of hand-picking is usually used to separate undesirable substance such as small piece of stones from wheat, rice and pulses.
(33) Ans: (i) Bring a magnet near this mixture several times. All the iron filings will stick to the magnet and get separated. We are then left with a mixture of sand and common salt.
(ii) Some water is added to the mixture of common salt and sand and stirred. Common salt dissolves in water to form salt solution, whereas sand remains undissolved.
(iii) On filtering, sand is obtained as a residue on the filter paper and salt solution is obtained as filtrate.
(iv) The salt solution is evaporated when pure common salt is left behind.
This mixture has been separated by using three methods of separation: magnetic separation, filtration and evaporation.
(34) (a) Sand and water from their mixture.
(b) Iron nails from saw-dust.
Ans: Magnetic separation
(35) Ans: Jewellers separate the pearls of different sizes by the method of sieving.
(36) Ans: By the method of concentration of ore through magnetic separation and hydraulic washing.
Long Answer Type Questions
(37) Sea-water is mixture of water. Common salt, and various other salts dissolved in it.
(38) Ans: The process of evaporation is used on a large scale to obtain common salt from sea-water. Sea-water is trapped in shallow lakes and allowed to stand there. The heat of sun gradually evaporates water in the shallow lakes and common salt is left behind as a solid.
(39) Ans: The mixtures are separated into their components for various purposes, such as:
(i) to remove an undesirable component,
(ii) to remove a harmful component,
(iii) to obtain the pure sample of a substance, and
(iv) to obtain a useful component.
- We make a cup of tea by boiling tea-leaves in water and then adding sugar milk. After the tea has been made, we remove the used tea-leaves from it before drinking it.
(40) Ans: Solid – Soli.
Liquid – Sea-water.
Gaseous – Air.
- Sugar is soluble in water whereas sand is insoluble in water. The mixture we could separated by evaporation.
(41) (a) Ans: A solution in which no more substance can be dissolved at that temperature, is called a saturated solution.
- If in a given solution, no more salt can be dissolved at that temperature, then that salt solution will be a saturated solution.
(b) Ans: (i) The solubility of a substance in water increases on increasing the temperature.
- (ii) The solubility of a substance decreases on lowering the temperature.
Multiple Choice Questions (MCQs)
(42) Ans: (c) magnet
(43) Ans: (b) evaporation
(44) Ans: (d) distillation
(45) Ans: (b) sieving
(46) Ans: (c) sand and sulphur
(47) Ans: evaporation
(48) Ans: (b) decantation
(49) Ans: (c) sugar
(50) Ans: (d) sand filters
(51) Ans: (c) hand-picking
(52) Ans: (c) evaporation followed by condensation.
(53) Ans: (d) sugar and salt
(54) Ans: (c) evaporation
(55) Ans: (c) sewing