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प्रश्न
How will you separate a mixture of iron filings, chalk powder and common salt ?
उत्तर
We will separate a mixture of iron filings, chalk powder and common salt by using a magnet followed by filtration and evaporation.
First, a magnet is moved on a mixture of iron filings, chalk powder and common salt. In the process, iron filings are separated by the magnet. After that, chalk powder and common salt are mixed in water. Salt dissolves in water but chalk powder does not. So, chalk powder is separated by filtration. On heating the filtrate, all the water is evaporated and salt crystals are left behind.
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संबंधित प्रश्न
Match the following
| Column A | Column B | ||
| (a) | Molecules | (i) | Water boils |
| (b) | 100° C | (ii) | Evaporation |
| (c) | 0° C | (iii) | Changes from solid to gas |
| (d) | At all temperatures | (iv) | Matter |
| (e) | Camphor | (v) | Water freezes |
Fill in the blank :
The substances which can flow are called ________
Name the terms for the change of vapour into a liquid.
Explain why, osmosis can be considered to be a special kind of diffusion. Classify the following into
(i) osmosis, and (ii) diffusion :
- swelling up of a raisin on keeping in water
- spreading of virus on sneezing
- earthworm dying on coming in contact with common salt
- shrinking of grapes kept in thick sugar syrup
- preserving of pickles in salt
- spreading of smell of cake being baked in the kitchen
- aquatic animals using oxygen dissolved in water during respiration
When extremely small particles X derived from the anther of a flower were suspended in a liquid Y and observed through a microscope, it was found that the particles X were moving throughout the liquid Y in a very zig-zag way. It was also observed that warmer the liquid Y, faster the particles X moved on its surface.
- What could particles X be ?
- What do you think liquid Y is ?
- What is the zig-zag movement of X known as ?
- What is causing the zig-zag movement of particles X ?
- Name the scientist who discovered this phenomenon.
- What does this experiment tell us about the nature of liquid Y?
What are pure substances ? Give two examples of pure substances.
Explain why, hydrogen and oxygen are considered elements whereas water is not considered an element.
What are (i) metals (ii) non-metals, and (iii) metalloids ? Give two examples each of metals, non-metals and metalloids.
Classify the following into metals, non-metals and metalloids:
Silicon, Mercury, Diamond, Sulphur, Iodine, Germanium, Sodium, Carbon, Magnesium, Copper, Boron, Helium
One of the following substances is neither a good conductor of electricity nor an insulator. This substance is :
Which one of the following is not a metalloid ?
Which of the following do not exhibit Tyndall effect ?
Starch solution, Sugar solution, Ink, Salt solution, Copper sulphate solution, Ammonium chloride solution, Fog, Smoke, Car exhausts.
One of the following is a solid foam. This one is :
How would you obtain sodium chloride from a mixture of sodium chloride and sulphur without using water ?
How will you separate camphor, common salt and iron nails from their mixture ?
Diffentiate between absorption and adsorption.
Atoms or groups of atoms having a charge are called ______.
Liquids cannot be compressed and they have fixed volume.
The fluidity of solids: ______.
Define the term matter.
