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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 ...................
उत्तर
The best evidence of the particles of matter are constantly moving comes from the studies of diffusion and Brownian motion.
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संबंधित प्रश्न
The smallest unit of matter that exists freely in nature is called ...........
What are the two conditions for the interconversion of states of matter ?
Name two processes which provide the best evidence for the motion of particles in matter.
When a crystal of potassium permanganate is placed in a beaker, its purple colour spreads throughout the water. What does this observation tell us about the nature of potassium permanganate and water?
In the following set of substances, one item does not belong to the set. Select this item and explain why it does not belong to the set :
Hydrogen, Oxygen, Steam, Chlorine
There is a large group of materials P which can be divided into three groups Q, R and S on the basis of their properties. The substances belonging to group Q can be solids, liquids or gases. The solids belonging to group Q are usually electrical insulators. Most of the substances of group R are solids which are good conductors of electricity. The substances belonging to group S are neither insulators like Q nor good conductors like R. The properties of S are intermediate between those of Q and R.
- What could the group of materials P be ?
- Name the substances Q. Give two examples of such substances.
- Name the substances R. Write two examples of such substances.
- Name the substances S. Give two examples of such substances.
- Out of Q, R and S, which substances are malleable and ductile ?
Choose the correct answer.
A 5 per cent sugar solution means that :
Define solvent.
Which of the following are chemical changes and which physical ? Give reason.
- a glass bottle breaking
- coal burning in air
- making a cake
- wool being knitted into a sweater
What type of magnet is fitted on a crane to separate scrap iron objects from a heap of waste materials in factories ?
Fill in the following blanks with suitable words :
A mixture of kerosene and petrol can be separated by .....................
Fill in the following blanks with suitable words :
The gases of air can be separated by fractional distillation of liquid air because they have different..............
What difference in the properties of common salt and sand would enable you to separate a mixture of these two substances ?
Justify your answer.
| Figure 1 | Figure 2 | Figure 3 |
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The arrangement of particles in three different phases of matter is shown above.
- Which state is represented by Fig. 1?
- In which state will the inter-particle attraction be maximum?
- Which one of them cannot be contained in an open vessel?
- Which one can take the shape of its container?
You want to wear your favourite shirt to a party, but the problem is that it is still wet after a wash. What steps would you take to dry it faster?
Solids possess very high kinetic energy.
The physical state of water at 373 K is ______.
Atoms are tiny particles that repel each other when they are squeezed very close.
The phenomenon of Evaporation takes place at the ______ of a liquid.
Give an example of a molecule.
