Give reason type question of chemistry class 9 lesson - Matter around as pure plz help me with the answer
Answers
Answer:
Question 1.
How can you change a saturated solution to an unsaturated solution without adding any more solvent to it?
Question 2.
Sucrose (sugar) crystals obtained from sugarcane and beetroot are mixed together. Will it be a pure substance or a mixture? Give reasons for the same.
Question 3.
Based on which factor a solution is said to be diluted, concentrated or saturated?
Question 4.
Identify solute and solvent in ‘tincture of iodine’.
Q.5. Assertion : When a beam of light is passed through a colloidal solution placed in a dark place the path of the beam becomes visible.
Reason : Light gets scattered by the colloidal particles.
Q.6. Assertion : A mixture of benzoic acid and naphthalene can be separated by crystallization from water.
Reason : Benzoic acid is soluble in hot water but naphthalene is insoluble in hot water.
Q.7. Assertion : A solution of table salt in a glass of water is homogeneous.
Reason : A solution having different composition throughout is homogeneous.
Q.8. Assertion : A mixture of sugar and benzoic acid can be separated by shaking with ether.
Reason : Sugar is insoluble in water.
Q.9. Assertion : In sublimation, a substance changes directly from solid to vapour without passing through
liquid state and vice-versa.
Reason : Distillation involves two processes i.e., vaporisation and condensation.
Question 10.
What is mass per cent of a solution?
Question 11.
What are the two components of a colloidal solution?
12.State whether the following statement is true or false:
Milk is a pure substance.
Question 13
Name three mixtures found in nature.
Question 14
Which of the following is a mixture?
Salt, Air, Water, Alum, Sugar
Multiple Choice Questions
Question 15.
Which of the following statements are true for pure substances?
(i) Pure substances contain only one kind of particles.
(ii) Pure substances may be compounds or mixtures.
(iii) Pure substances have the same composition throughout.
(iv) Pure substances can be exemplified by all elements other than nickel.
(a) (i) and (ii)
(b) (i) and (iii)
(c) (iii) and (iv)
(d) (ii) and (iii)
Question 16.
Rusting of an article made up of iron is called
(a) corrosion and it is a physical as well as chemical change
(b) dissolution and it is a physical change
(c) corrosion and it is a chemical change
(d) dissolution and it is a chemical change.
Question 17.
A mixture of sulphur and carbon disulphide is
(a) heterogeneous and shows Tyndall effect
(b) homogeneous and shows Tyndall effect
(c) heterogeneous and does not show Tyndall effect
(d) homogeneous and does not show Tyndall effect.
Question 18.Two substances, A and B were made to react to form a third substance, A2B according to the following reaction 2A + B → A2 B. Which of the following statements concerning this reaction are incorrect?
(i) The product A2B shows the properties of substances A and B.
(ii) The product will always have a fixed composition.
(iii) The product so formed cannot be classified as a compound.
(iv) The product so formed is an element.
(a) (i), (ii) and (iii) (b) (ii), (iii) and (iv)
(c) (i), (iii) and (iv) (d) (ii), (iii) and (iv)
Q.19. Give two examples each for: (i) Aerosol, (ii) Emulsion. In what way are they different?
Q.20.State the principle of separating two immiscible liquids by separating funnel. Describe an activity with diagram to separate a mixture of water and kerosene oil.