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प्रश्न
What is meant by saying that metals are lustrous ?
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उत्तर
Metals are said to be lustrous because of their property to shine.
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संबंधित प्रश्न
Name the processes involved in two cases.
Name the terms for the change of vapour into a liquid.
Which type of elements, metals or non-metals, show the property of brittleness ?
What is meant by saying that non-metals are brittle ?
Name a metal which is yellow in colour.
There is a large group of materials P which can be divided into three groups Q, R and S on the basis of their properties. The substances belonging to group Q can be solids, liquids or gases. The solids belonging to group Q are usually electrical insulators. Most of the substances of group R are solids which are good conductors of electricity. The substances belonging to group S are neither insulators like Q nor good conductors like R. The properties of S are intermediate between those of Q and R.
- What could the group of materials P be ?
- Name the substances Q. Give two examples of such substances.
- Name the substances R. Write two examples of such substances.
- Name the substances S. Give two examples of such substances.
- Out of Q, R and S, which substances are malleable and ductile ?
A, B and C are all liquids. Liquid A has a comparatively low boiling point. On heating, liquid A vaporises completely without leaving behind any residue. Liquid A is being used increasingly as a fuel in motor vehicles either alone or by mixing with petrol. Liquid B has a very high boiling point. It also vaporises completely on heating, without leaving any residue. Liquid B is a conductor of electricity and used in making thermometers. Liquid C has a moderate boiling point. On heating, liquid C vaporises leaving behind a white solid D which is used in cooking vegetables. The condensation of vapours from C give a liquid E which turns anhydrous CuSO4 to blue.
(a) Which liquid could be an element ? Name this element.
(b) Which liquid could be a mixture ? Name this mixture.
(c) Which liquid could be a compound ? Name this compound.
(d) What could the solid D be ?
(e) What do you think is liquid E ?
How much water should be added to 15 grams of salt to obtain 15 per cent salt solution ?
Choose one term from the following which includes the other three :
aerosol, emulsion, colloid, sol
What is the difference between solutions and colloids ?
Define solubility of a substance. How does it vary with temperature ?
Tincture of iodine has antiseptic properties. This solution is made by dissolving :
Name the property of one of the constituents which can be used to separate a mixture of salt and iodine
Explain how, impure copper sulphate can be purified by crystallisation.
The dyes present in fountain pen ink can be separated by the technique of :
Matter is made up of ______.
Name the metals that are used in jewellery.
All the matter made of ______.
Which among the following is not a matter?
Match the physical quantities given in column A to their S I units given in column B:
| (A) | (B) | ||
| (a) | Pressure | (i) | cubic metre |
| (b) | Temperature | (ii) | kilogram |
| (c) | Density | (iii) | pascal |
| (d) | Mass | (iv) | kelvin |
| (e) | Volume | (v) | kilogram per cubic metre |
