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प्रश्न
State whether the following statement is true or false :
Bread is an example of solid foam.
विकल्प
True
False
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उत्तर
True. Solid foam allows the gas to get dispersed in solid medium.
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संबंधित प्रश्न
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 ...................
Name the scientist who studied the movement of pollen grains suspended in water through a microscope. What is this phenomenon known as?
Explain why, hydrogen and oxygen are considered elements whereas water is not considered an element.
Choose one term from the following which includes the other three :
aerosol, emulsion, colloid, sol
Explain what happens when a beam of light is passed through a colloidal solution.
Define Foam Give one example.
Define solubility of a substance. How does it vary with temperature ?
One of the following liquids will leave behind a residue on heating. This one is :
The solubility of ammonium chloride in water at various temperatures is given below :
| 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 ?
Name the source from which nitrogen and oxygen are obtained on a large scale.
What is the general name of the process by which tea-leaves are separated from prepared tea ?
How will you separate iron pins from sand ?
Describe the various steps involved in the separation of iodine, iron filings and salt from a mixture.
Which of the following mixture cannot be separated by using water as the solvent ?
A solid mixture contains four constituents P, Q, R and S. P consists of tiny grains and it is mixed with
cement for plastering the walls. Q is a white solid which is recovered on a large scale from sea water by the
process of evaporation. R is in the form of tiny particles of a material whose corrosion is called rusting. And
S is a white solid which is used in making ordinary dry cells.
- What could P, Q, R and S be ?
- How would you separate a mixture containing P, Q, R and S ?
If there is a sudden shower, we take shelter under a roof at the roadside. Even though the rain does not fall on us directly, we get wet to some extent. Why ?
The most reactive metal is ______.
Complete the following table:
| S.No. | CELSIUS | KELVIN |
| 1. | 90°C | 363 K |
| 2. | ______ | 283 K |
| 3. | 63 °C | ______ |
| 4. | 250°C | ______ |
| 5. | ______ | 303 K |
Atoms are tiny particles that repel each other when they are squeezed very close.
A teabag placed in a cup of hot water will diffuse into the water.
