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प्रश्न
Why do we need pure substances?
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उत्तर
We need pure substances because of the following reasons:
- A pure substance has a fixed melting and fixed boiling point.
- A pure substance has its characteristic taste, colour, and odour.
- Pure substances can not be broken further into more simple substances by any physical means.
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संबंधित प्रश्न
Compare the properties of metals and non-metals with respect to
- alleability
- ductility
- electrical conductivity.
Name the property of any one of the components which can be used for separating the following mixture :
Salt and Camphor
Tick (√) the correct alternative from the choice given for the following statement:
Copper is not a part of the alloy
Match the statements in List I with the correct answer in List II.
| List I | List II |
| 1. Purification of water by adding alum | A: Sublimation |
| 2. Seawater leaving behind common salt | B: Sieving |
| 3. Separation of camphor and potassium chloride | C: Filtration |
| 4. Separation of charcoal from a charcoal-water mixture | D: Sedimentation |
| 5. Separation of bran and wheat flour | E: Evaporation |
State whether the following statement is true or false. If false write – the correct statement.
Components in a mixture are present in a definite proportion.
State whether the following statement is true or false. If false write – the correct statement.
Components in a mixture can be separated by physical and chemical methods.
Select the correct answer from the choice in the bracket.
A homogenous mixture.
Write the sequence of steps you would use for making tea. (Use the words: mixture, dissolve, filtrate and residue).
Suggest separation technique(s) one would need to employ to separate the following mixture.
Common salt, water and sand
Under which category of mixtures will you classify alloys and why?
