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प्रश्न
What is the general name of the materials which contain at least two pure substances and show the properties
of their constituents ?
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उत्तर
Materials that are made up of two or more pure substances and show the properties of their constituents are called mixtures.
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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 |
Select the correct alternative
The molecules can move freely anywhere in
- gases
- liquids
- solids
- none of the above
Fill in the following blank with suitable words :
The best evidence that the particles of matter are constantly moving comes from the studies of ................. and ...................
Bromine and air take about 15 minutes to diffuse completely but bromine diffuses into a vacuum very rapidly. Why is this so?
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
Name one element, one compound and one mixture.
What are the three groups into which all the elements can be divided ? Name two elements belonging to each group.
State any two properties for believing that aluminium is a metal.
Name a metal which is yellow in colour.
Iron powder and sulphur powder were mixed together and divided into two parts A and B. When part A was heated strongly over a burner, then a substance C was formed. The part B was, however, not heated at all. When dilute hydrochloric acid was added to substance C, then gas D was evolved and when dilute hydrochloric acid was added to part B then gas E was evolved.
- What type of substance is B ?
- What type of substance is C ?
- Name the gas (i) D, and (ii) E ?
- State one characteristic property of gas D.
- Write one test to identify gas E.
If 25 mL of acetone is present in 150 mL of its aqueous solution, calculate the concentration of solution.
Define solubility of a substance. How does it vary with temperature ?
Name the process which can be used to recover salt from an aqueous salt solution.
What difference in the properties of oil and water enable their separation by a separating funnel ?
Name the process which can be used to purify an impure sample of copper sulphate.
Describe the method of separating a mixture containing common salt, sand and ammonium chloride.
Which method is better for recovering sugar from sugar solution : evaporation or crystallisation ? Give reason
for your answer.
The technique which is used to separate particles of a solid suspended in a liquid quickly is called :
Select the correct answer from A, B, C, D & E for the statement given below:
An atom or group of atoms _________ having a resultant charge.
Gases do not diffuse very easily.
