Chapter 2 - Is Matter Around Us Pure | Exam Idea Class 9 - Page 2 Of 6

Iron filings and sulphur were mixed together and divided into two parts ‘A and S, Part A, was heated strongly while Part ‘S’ was not heated. Dilute hydrochloric acid was added to both the parts and evolution of gas was seen in both the cases. How will you identify the gases evolved?

Part A 𝐹𝑒(𝑠) + 𝑆(𝑠) → 𝐻𝑒𝑎𝑡 𝐹𝑒𝑆(𝑠) 𝐹𝑒𝑠(𝑠) + 2𝐻𝐶𝑙(𝑎𝑞) → 𝐹𝑒𝐶𝑙2(𝑎𝑞) + 𝐻2𝑆(𝑔) Part B Fe(s) + S(s) → Mixture of iron filings and sulphur When dilute…

Show diagrammatically how water is purified in the waterworks system and list the processes involved.

Classify each of the following as a physical or a chemical change. Give reasons. (a) Drying of a shirt in the sun. (b) Rising of hot air over a radiator. (c) Burning of kerosene in a lantern. (d) Change in the colour of black tea on adding lemon juice to it. (e) Churning of milk cream to get butter.

(a) It is a physical change because water is converted from its liquid state to gaseous state because of the sun's heat. (b) It is a physical change because water…

You are provided with a mixture containing sand, iron filings, ammonium chloride and sodium chloride. Describe the procedures you would use to separate these constituents from the mixture.

(i) Removing iron filings from the mixture by magnetic separation: Take the mixture in a petri dish and roll a bar magnet over it. Iron filings will get attach to…

A child wanted to separate the mixture of dyes constituting a sample of ink. He marked a line by the ink on the filter paper and placed the filter paper in a glass containing water as shown in figure. The filter paper was removed when the water moved near the top of the filter paper. (i) What would you expect to see, if the ink contains three different coloured components? (ii) Name the technique used by the child. (ii) Suggest one more application of this technique.

(i) The colour component which is more soluble in water dissolves first, rises faster and produces a colour band (spot) on the paper at a higher position. The less soluble…

$Read more about the article Fractional distillation is suitable for separation of miscible liquids with a boiling point difference of about 25 K or less. What part of fractional distillation apparatus makes it efficient and possess an advantage over a simple distillation process? Explain using a diagram.$

Fractional distillation is suitable for separation of miscible liquids with a boiling point difference of about 25 K or less. What part of fractional distillation apparatus makes it efficient and possess an advantage over a simple distillation process? Explain using a diagram.

The fractionating column packed with glass beads provides a surface for the vapours to collide and lose energy so that they can be quickly condensed and distilled. Also, length of…

A group of students took an old shoe box and covered it with a black paper from all sides. They fixed a source of light (a torch) at one end of the box by making a hole in it and made another hole on the other side to view the light. They placed a milk sample contained in a beaker/tumbler in the box as shown in the figure. They were amazed to see that milk taken in the tumbler was illuminated. They tried the same activity by taking a salt solution but found that light simply passed through it. (a) Explain why the milk sample was illuminated. Name the phenomenon involved. (b) Same results were not observed with a salt solution. Explain. (c) Can you suggest two more solutions which would show the same effect as shown by the the milk solution?

(a) Milk is a colloid. If a beam of light is put on a milk sample contained in a beaker, the path of light beam is illuminated and becomes visible…

Iron filings and sulphur were mixed together and divided into two parts ‘A and S, Part A, was heated strongly while Part ‘S’ was not heated. Dilute hydrochloric acid was added to both the parts and evolution of gas was seen in both the cases. How will you identify the gases evolved?

Show diagrammatically how water is purified in the waterworks system and list the processes involved.

Classify each of the following as a physical or a chemical change. Give reasons. (a) Drying of a shirt in the sun. (b) Rising of hot air over a radiator. (c) Burning of kerosene in a lantern. (d) Change in the colour of black tea on adding lemon juice to it. (e) Churning of milk cream to get butter.

You are provided with a mixture containing sand, iron filings, ammonium chloride and sodium chloride. Describe the procedures you would use to separate these constituents from the mixture.

Fractional distillation is suitable for separation of miscible liquids with a boiling point difference of about 25 K or less. What part of fractional distillation apparatus makes it efficient and possess an advantage over a simple distillation process? Explain using a diagram.

Distinguish between compounds and mixtures.

Distinguish between metals and non-metals.

Distinguish between physical change and chemical change.

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