Extra Questions For Class 9 Science Chapter 2 Is Matter Around Us Pure

Extra Questions For Class 9 Science Chapter 2 Is Matter Around Us Pure

Very Short Answer Type Questions (One Mark Each)

Q.1. Suggest separation techniques one would need to employ to separate the mixtures :
(a) Mercury and water
(b) Potassium Chloride and ammonium chloride.

Answer

Ans. (a) Using separating funnel.
(b) Using sublimation.

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Q.2 Salt can be recovered from solution by evaporation. Suggest some other for the same.

Answer

Ans. By crystallisation and distillation.

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Q.3. Name the first scientist who used the term element.

Answer

Ans. Robert Boyle (1661).

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Q.4. Name a metal which is liquid.

Answer

Ans. Mercury is the only metal that is liquid at room temperature.

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Q.5. Metals make a ringing sound when hit. What is this property known as ?

Answer

Ans. Sonorous.

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Q.6. Are soft drinks mixtures or pure compounds ?

Answer

Ans. Soft drinks are mixtures.

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Q.7. Give the constituents of soda water.

Answer

Ans. Sugar, water and carbon dioxide are the constituents of soda water.

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Q.8. Do constituents of a mixture retain their characteristic properties ? Say Yes’ or ‘no’?

Answer

Ans. Yes.

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Q.9. Is solution homogeneous or heterogeneous in nature ?

Answer

Ans. Solution is a homogeneous mixture.

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Q.10. Give one example of a solid solution.

Answer

Ans. Brass. It is homogeneous mixture of approximately 70% copper and 30% zine.

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Q.11. Give two examples of homogeneous mixtures.

Answer

Ans. Salt in water, sugar in water, copper sulphate solution in water or potassium permanganate solution.

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Q.12. Give two examples of heterogeneous mixtures.

Answer

Ans. Mixtures of sodium chloride and iron filings, oil and water and salt and sulphur.

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Q.13. Give two examples of a colloidal solution.

Answer

Ans. Milk, ink, gum, smoke, blood.

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Q.14. What method will you use to separate the components of a sodium chloride solution ?

Answer

Ans. Evaporation.

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Q.15. Name the process used by milkman to separate cream from milk.

Answer

Ans. Centrifugation.

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Q.16. You are given a mixture of camphor and salt. Which method you will use to separate the components of this mixture ?

Answer

Ans. Sublimation

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Q.17. Can we separate a mixture of camphor and naphthalene by sublimation ? Support your answer with reason.

Answer

Ans. No. Because both the components undergo sublimation.

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Q.18. Sulphuric acid is added to water. Will you get a mixture or a compound?

Answer

Ans. We will get a mixture because its components may be in any proportion.

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Q.19. In the process of chromatography, an ink drop splits up into three spots on filter paper strip. What do you conclude from this observation ?

Answer

Ans. It indicates that dye in the ink drop consists of three different components.

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Q.20. Lighting of a bulb in your room is a physical or chemical change ?

Answer

Ans. It is a physical change.

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Q.21. Can physical and chemical changes occur simultaneously. Comment.

Answer

Ans. Yes. Burning of a candle involves both physical and chemical changes.

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Q.22. State one difference between pure and impure substances.

Answer

Ans. Pure substances contain only one type of particles while impure substances contain more than one type of particles.

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Q.23. Identify solute and solvent in 80% solution of ethyl alcohol with water.

Answer

Ans. Ethyl alcohol (80%) – solvent
Water (20%) – solute.

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Q.24. Select the substances from the following which do not have the property of sublimation :
Camphor, potassium permanganate, copper sulphate, naphthalene.

Answer

Ans. Potassium permanganate and copper sulphate do not have the property of sublimation.

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Q.25. Name the technique to separate oil from water and also the principle involved in their separation.

Answer

Ans. A separating funnel is used to achieve the separation. Principle : Immiscible liquids form separate layers in the mixture.

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Q.26. What is the advantage of fractional distillation over simple distillation ?

Answer

Ans. Fractional distillation can be used even when the boiling points of components are close to one another.

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Q.27. The wool being knitted into a sweater is a physical change. Justify the statement.

Answer

Ans. The sweater can be deknitted to obtain wool with no change in property.

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Q.28. Classify brass and diamond as element and mixture.

Answer

Ans. Brass – Mixture. Diamond – Element.

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Q.29. Identify non-metals from the following elements : Carbon, potassium, silicon, chlorine, mercury.

Answer

Ans. Carbon and silicon are non-metals.

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Q.30. Why does the solution of sodium chloride not show Tyndall effect whereas the mixture of water and milk shows ?

Answer

Ans. Sodium chloride forms a true solution in water and the particle size of sodium chloride is small and does not scatter light. Milk and water form a colloidal solution. A colloidal solution scatters light and shows Tyndall effect.

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Q.31. Give two examples from daily life where Tyndall effect is observed.

Answer

Ans. (i) When sunlight passes through the canopy of a dense forest.
(ii) When a fine beam of light enters a room through a small hole.

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Q.32. Classify the following into element or compound :
(a) Carbon
(b) Carbon monoxide.

Answer

Ans. (a) Carbon – Element
(b) Carbon monoxide – Compound

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Q.33. Name a non-metal which (a) is lustrous (b) exists as a liquid at room temperature.

Answer

Ans. (a) Iodine
(b) Bromine

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