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प्रश्न
State whether the following statement is true or false :
Bread is an example of solid foam.
पर्याय
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
What are the conditions for 'something' to be called 'matter'?
Name the scientist who studied the movement of pollen grains suspended in water through a microscope. What is this phenomenon known as?
Define matter. Give four examples of matter.
What name is given to those elements which are neither good conductors of electricity like copper nor insulators like sulphur ?
Fill in the following blanks with suitable words :
Brass is an alloy which is considered a ..............
Fill in the following blanks with suitable words :
The elements which are sonorous are called ..........................
What are the three groups into which all the elements can be divided ? Name two elements belonging to each group.
Name a metal which forms amalgams.
Classify the following into metals, non-metals and metalloids:
Silicon, Mercury, Diamond, Sulphur, Iodine, Germanium, Sodium, Carbon, Magnesium, Copper, Boron, Helium
Which of the following statements are true for pure substances ?
- pure substances contain only one kind of particles
- pure substances may be compounds or mixtures
- pure substances have the same composition throughout
- pure substances can be exemplified by all elements other than nickel
Which of the following contains less solute at a given temperature and pressure ? Unsaturated solution or Saturated solution.
Define the emulsion. Give one example.
Which one of the following is not a chemical change ?
One of the following represents the solution of solid in a solid. This one is :
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.
Describe the various steps involved in the separation of iodine, iron filings and salt from a mixture.
How is cream separated from milk ?
The technique which is used to separate particles of a solid suspended in a liquid quickly is called :
Diffentiate between absorption and adsorption.
Liquids cannot be compressed and they have fixed volume.
