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Matter: |
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What is matter?
Matter is all around us. Anything that can be felt by one or more of our senses is matter. It is anything that occupies space, contains mass, has volume, and offers resistance. Everything in this world is either matter or energy and they are both inter-convertible i.e. matter can be converted into energy and energy can be converted into matter.
And hence the formula by Einstein: E=mC2 where E is energy, m is mass and C is the speed of light. LAW OF CONSERVATION OF MATTER, “ENERGY CAN NEITHER BE CREATED, NOR BE DESTROYED”. |
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Matter consists of very minute particles called ‘atoms’. These particles give matter its form. |
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Characteristics of matter: |
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 These particles are never stationary. The particles are always in a state of movement and more the tendency of the particles to move, more their thermal energies are. |
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The particles attract each other. These particles have a tendency attract each other and more the distance between two particles, less they attract each other. |
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The particles have space between them. All the particles in matter have distance between them which ranges from 10-8 to 10-5. These empty spaces directly affect the spontaneous intermingling of the particles of two or more substances as a result of thermal motion. |
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The atoms or molecules have some energy within them, the level of which decides the state in which the matter is. The level of energy rises when heat is applied to matter as a result of which the state of matter can change. |
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THE PHYSICAL CLASSIFICATION OF MATTER:
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Matter when classified physically, can be found in three forms
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Solid: |
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The particles of matter in solid state have least energy. The intermolecular space is minimum i.e. the molecules are closely packed and therefore the matter in solid state is almost incompressible. These particles attract each other highly thereby restricting their freedom of movement. Therefore, most solids have a definite shape and volume. Solids have the following features: |
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They have a definite shape. |
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They have a definite volume. |
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They are incompressible. |
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They are incompressible. |
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They offer resistance to the deformation of their shape. |
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They have a high density. |
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They have a high melting point. |
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They have a high boiling point. |
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Most solids convert to liquids when heat energy is applied to them. |
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They are usually very rigid. |
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Solids are of two types:
Crystalline
Amorphous.
Crystalline structures are characterized externally by a well-defined, three dimensional, geometric shape.
Amorphous structures have no definite, clear shape. They do not have a defined melting point and have a tendency to lose shape more easily. |
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Liquid: |
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The particles of matter in a liquid state have medium level of energy. The inter-molecular space between particles is more as compared to solids and therefore the attraction between them is comparatively less. The liquids have a tendency to flow because they have a definite volume but no specific shape; in fact liquids take the shape of the container they are put in and they have just one free surface.
Liquids have the following features: |
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 They have a definite volume but no definite shape.
It is non compressible
It can flow without dispersal
The boiling points of all liquids are above the room temperature.
They usually have a low density.
They are not very rigid |
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Gaseous: |
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The inter-molecular spaces between the particles in a gaseous form of matter are very large i.e. the molecules are closely packed. Gases have no definite shape and volume. They take the shape and volume of the container they are put in. it has no free surface in fact gases have no surface of their own.
Gases have the following features: |
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 Gases have no definite shape
They have no definite volume, their volume depends upon the pressure and temperature
They have no surface of their own
It is fluid
It is highly compressible·
They have a low density·
They are not rigid at all. |
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Conversion of the states of matter:
State of Matter depends on the temperature and pressure that is applied to it. The state of matter is convertible. Solids can be converted into liquids when heat energy is applied to it and similarly liquids can be converted into gases upon the application of heat energy. Also, when gases are cooled down, they gradually convert into liquids and similarly when liquids are cooled, they convert back into solids.
This can be better understood by an example.When ice i.e. solid, is heated, it converts into water i.e. liquid. On heating water we get water vapor i.e. gas. Similarly on cooling the water vapors, it gradually forms water and on further cooling, it forms ice.It is to be kept in mind that all compounds do not convert from solid to liquid on heating.
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