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NCERT solutions Science Textbook for Class 9 chapter 2 Is Matter around us Pure

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Chapter 2 - Is Matter around us Pure

Page 15

What is meant by a substance?

Q 1 | Page 15 |

Pages 28 - 30

Which separation techniques will you apply for the separation of the Sodium chloride from its solution in water.

Q 1.1 | Page 28 |

Which separation techniques will you apply for the separation of the Ammonium chloride from a mixture containing sodium chloride and ammonium chloride.

Q 1.2 | Page 28 |

Which separation techniques will you apply for the separation of the Small pieces of metal in the engine oil of a car.

Q 1.3 | Page 28 |

Which separation techniques will you apply for the separation of the Different pigments from an extract of flower petals.

Q 1.4 | Page 28 |

Which separation techniques will you apply for the separation of the Oil from water.

Q 1.5 | Page 28 |

Which separation techniques will you apply for the separation of the Tea leaves from tea.

Q 1.6 | Page 28 |

Which separation techniques will you apply for the separation of the Fine mud particles suspended in water.

Q 1.7 | Page 28 |

Write the steps you would use for making tea. Use the words: solution, solvent, solute, dissolve, soluble, insoluble, filtrate and residue.

Q 2 | Page 28 |

Pragya tested the solubility of three different substances at different temperatures and collected the data as given below( results are given in the following table, as grams of substance dissolved in 100 grams of water to form a saturated solution).

Substance dissolved Temperature in K
283 293 313 333 353
Potassium nitrate 21 32 62 106 167
Sodium chloride 36 36 36 37 37
Potassium chloride 35 35 40 46 54
Ammonium chloride 24 37 41 55 66

(a)  What mass of potassium nitrate would be needed to produce a saturated solution of potassium nitrate in 50 grams of water at 313 K?

(b)  Pragya makes a saturated solution of potassium chloride in water at 353 K and leaves the solution to cool at room temperature. What would she observe as the solution cools? Explain.

(c)  Find the solubility of each salt at 293 K. What salt has the highest solubility at this temperature?

(d)  What is the effect of change of temperature on the solubility of a salt?

Q 3 | Page 28 |

Explain the term Pure substance by giving examples.

Q 4.2 | Page 29 |

Explain the term Colloid by giving examples.

Q 4.3 | Page 29 |

How would you confirm that a colourless liquid given to you is pure water?

Q 6 | Page 29 |

Identify the solutions among the following mixtures:-

(a) Soil

(b) Sea water

(c) Air

(d) Coal

(e) Soda water

Q 8 | Page 29 |

Which of the following will show the “Tyndall effect”?

(a) Salt solution

(b) Milk

(c) Copper sulphate solution

(d) Starch solution

Q 9 | Page 29 |

Which of the following are chemical changes?

(a) Growth of a plant

(b) Rusting of iron

(c) Mixing of iron fillings and sand

(d) Cooking of food

(e) Digestion of food

(f) Freezing of water

(g) Burning of candle

Q 11 | Page 30 |

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