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प्रश्न
Pure copper sulphate can be obtained from an impure sample by the process of :
पर्याय
evaporation
fractional distillation
centrifugation
crystallisation
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उत्तर
crystallization
Crystallization is the process of cooling a hot concentrated solution of a substance to obtain its crystals in pure form.
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संबंधित प्रश्न
Name the processes involved in two cases.
Which of the following materials fall in the category of a “pure substance”?
- Ice
- Milk
- Iron
- Hydrochloric Acid
- Calcium oxide
- Mercury
- Brick
- Wood
- Air
What is Brownian motion? Draw a diagram to show the movement of a particle (like a pollen grain during Brownian motion.
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
During respiration, glucose and oxygen enter our body cells and waste products carbon dioxide and water leave the body cells by the process of :
Name a metal which is soft and a non-metal which is hard.
Name the property which allows metals to be hammered into thin sheets.
Classify the following into elements and compounds :
- H2O
- He
- Cl2
- CO
- Co
Classify the following as elements or compounds :
Iron, Iron sulphide, Sulphur, Chalk, Washing soda, Sodium, Carbon, Urea
Which of the following are ‘pure substances’ ?
Ice, Milk, Iron, Hydrochloric acid, Calcium oxide, Mercury, Brick, Wood, Air
Name a non-metal :
- which is lustrous
- which is required for combustion
- whose one of the allotrophic forms is a good conductor of electricity. Name the allotrope.
- other than carbon which shows allotropy
- which is known to form the largest number of compounds
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
Calculate the concentration of a solution which contains 2.5 g of salt dissolved in 50 g of water.
In what respects does a true solution differ from a colloidal solution ?
What difference in the property of two miscible liquids enables their separation by fractional distillation ?
How is the impurity of iron present in several substances removed in industries ?
How will you separate a mixture of common salt, sulphur powder and sand ?
The material which is added to water during purification process at the water works so as to disinfect it is :
Name the metals that are used in jewellery.
Solids possess very high kinetic energy.
