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प्रश्न
Name a non-metal which is a good conductor of electricity.
उत्तर
Graphite is a non-metal that is a good conductor of electricity.
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संबंधित प्रश्न
Gases have definite volume but no definite shape.
Give one difference between atoms and molecules.
What is the scientific name of particles which make up mater?
When a crystal of potassium permanganate is placed in a beaker, its purple colour spreads throughout the water. What does this observation tell us about the nature of potassium permanganate and water?
Define matter. Give four examples of matter.
Name one solid, one liquid and one gaseous non-metal.
Which of the following are ‘pure substances’ ?
Ice, Milk, Iron, Hydrochloric acid, Calcium oxide, Mercury, Brick, Wood, Air
Which of the following substances are elements ?
Water, Salt, Mercury, Iron, Marble, Diamond, Wood, Nitrogen, Air, Graphite, Hydrogen, Oxygen, Sugar, Chlorine
Name a metal which is yellow in colour.
Which of the following are not compounds ?
Chlorine gas, Potassium chloride, Iron powder, Iron sulphide, Aluminium foil, Iodine vapour, Graphite, Carbon monoxide, Sulphur powder, Diamond
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Milk is a .................... solution but vinegar is a .................... solution.
When the solid A is added to water, it dissolves with the evolution of a lot of heat and making little explosions to form two products B and C. The properties of products B and C are entirely different from those of solid A as well as water. Moreover, products B and C cannot be reconverted into solid A and water. When another solid D is added to water, it dissolves with the absorption of a little heat to form a product E which cools down. The product E shows the properties of both, solid D as well as water. Moreover, product E can be converted into solid D and water.
(a) What type of change occurs when solid A is dissolved in water ? Why ?
(b) What type of change occurs when solid D is dissolved in water ? Why ?
(c) Name a metal which you think could behave like solid A. Also name the products B and C.
(d) Name the solid D if it is the one which is used in making ordinary dry cells.
(e) Name the process by which D can be recovered from E.
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| Temperature | : | 10°C | 20°C | 40°C | 60°C | 80°C |
| Solubility | : | 24 g | 37 g | 41 g | 55 g | 66 g |
What mass of ammonium chloride would be needed to make a saturated solution of ammonium chloride in fifty grams of water at 40°C ?
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Non-metals are usually poor conductors of heat and electricity. They are non-lustrous, non-sonorous, non-malleable and are coloured.
Name a non-metal which exists as a liquid at room temperature.
Evaporation does form bubbles.
