Very Short Answers - Is Matter Around Us Pure, Science, Class 9 PDF Download

Q1. Define solvent.
Ans. The component of the solution that dissolves the other component in it is called the solvent.

Q2. Define solute.
Ans. The component of the solution that is dissolved in the solvent is called solute.

Q3. What is ‘tincture of iodine’?
Ans. A solution of iodine in alcohol is known as tincture of iodine. It has iodine (solid) as the solute and alcohol (liquid) as the solvent.

Q4. What are alloys?
Ans. The homogeneous mixture of two or more metals or a metal and non-metal is called an alloy. E.g., steel is an alloy of iron and carbon.

Q5. Give one example of gas in liquid solution.
Ans. Cold-drinks, carbon dioxide gas as solute is mixed with water as a solvent.

Q6. How can a solution be dilute or concentrated?
Ans. The amount of solute dissolved in a solvent decides whether the solution is dilute or concentrated.

Q7. What is “concentration of a solution”?
Ans. The concentration of a solution is the amount of solute present in a given amount of solution or the amount of solute dissolved in a given mass or volume of solvent.

Q8. State the difference between aqueous and non-aqueous solution.
Ans. Aqueous solutions have water as solvent and non-aqueous solutions do not have water as solvent.

Q9. What is “solubility” of a solute?
Ans. The amount of the solute present in the saturated solution at the given temperature is called its solubility.

Q10. What is saturated solution?
Ans. The maximum amount of solute that can be dissolved in a solvent at given temperature is called saturated solution, where no more solute can dissolve further.

Q11. What is unsaturated solution?
Ans. If the amount of solute contained in a solution is less than the saturation level, it is called an unsaturated solution.

Q12. How can you convert saturated solution into unsaturated or vice-versa?
Ans. Saturated solution on heating becomes unsaturated and unsaturated solution on cooling becomes saturated.

Q13. Why water is called universal solvent?
Ans. Water can dissolve large number of substances in it.

Q14. What is Tyndall effect?
Ans. The scattering of light by colloidal particles is known as Tyndall effect.

Q15. How can we separate colloidal mixtures?
Ans. By centrifugation, in a centrifuge machine the colloidal solution is kept in a test tube, rotated very fast and due to centrifugal force the colloidal particles are separated.

Q16. What is emulsion?
Ans. When both the dispersed phase and dispersing medium is liquid, it is called emulsion. E.g., milk, face cream.

Q17. What is aerosol?
Ans. When the solid or liquid is dispersed in a gas it is called aerosol. E.g., smoke, fog.

Q18. What is the principle for separation of immiscible liquids?
Ans. The principle of separating immiscible liquids into layers depends on their densities. The less denser liquid collects at the top and more denser liquid at the bottom.

Q19. What is chromatography?
Ans. Chromatography is the technique used for separation of those solutes that dissolve in the same solvent.

Q20. What is distillation?
Ans. Distillation is the separation technique of two miscible liquids that boils without decomposition and have sufficient difference in their boiling points.

Q21. How can you separate two liquids that have less than 25 K difference of boiling points?
Ans. To separate a mixture of two or more miscible liquids for which the difference in boiling points is less than 25 K, is fractional distillation.

Q22. What is condenser?
Ans. It is an apparatus used to convert gas into liquid by cooling it.

Q23. What is crystallisation?
Ans. When a saturated solution is heated and allowed to cool slowly, crystal of the solute dissolved in the saturated solution are separated from it. It is used to purify solids.

Q24. How will you separate miscible and immiscible liquids?
Ans. Miscible liquid can be separated by distillation and immiscible liquids can be separated by using separating funnel.