Chapter 1- Matter
🌈 Rainbow mind map
Matter
Definition- Matter is anything which occupies space and has mass. There are
three states of matter are
1. Solid,
3. Gas
Composed of:- Molecules, the smallest unit which can exist freely in nature and always in state of motion, posses K.E.
- As solids, molecules are rigid, the inter-molecular
spacing is least, the inter-molecular forces are strongest and the
molecules remain in their fixed positions. They vibrate to and fro about
their mean positions, but they do not leave their positions, so a solid
has a definite shape and a definite volume.
- In a liquid, the molecules are not rigid,
the inter-molecular spacing is more than that in solids, the
inter-molecular forces are weak and the molecules are free to move within
the boundary of the liquid, so the liquid has a definite volume, but it
does not have a definite shape.
- In gases, the molecules are not rigid, the inter-molecular spacing is more than that in solids and liquids, the inter-molecular forces are weakest and the molecules are free to move anywhere in space. So the gas has neither a definite volume nor a definite shape
2. Liquid to Solid - Freezing
3. Liquid to Gas - Vaporization /
Boiling
4. Gas to Liquid- Condensation
5. Solid to Gas - Sublimation
6. Gas to solid – deposition
Terms related-
●Evaporation- change of state from liquid to gas at any temperature. Factors affecting –
i) Temperature of a liquid
ii) Area if surface exposed
ii) Nature of liquid
iv) Blow of air above liquid
v) Presence of humidity
● Cohesive force-“Force of attraction between same kind of
molecules.
● Adessive force- Force of attraction between different kind of
molecules.
● Latent heat of Fusion- Amount of heat needed to convert 1kg of
ice at 0⁰C into water at 0⁰C.
●Latent heat of vaporization- Amount of heat needed to convert 1 kg of water
at 100⁰C to steam at 100⁰C .
Let’s perform:-
Activity 1:-
Certain quantity of water taken in a beaker with
thermometer in it. It is heated.
Observation- i)Temperature
of water taken = 30⁰C
ii) On heating, temperature on thermometer is
observed to be increasing .
iii) At 100⁰C , change of state takes place, temperature ,further does not change.
Conclusion-
i)
Water boils at 100⁰C
ii)
When change of state takes place, there is no
increase of temperature .
iii)
At boiling, heat is used up to change the state
.
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| Activity 1 |
Activity 2:-
1kg of ice at 0⁰C is taken
in a beaker with thermometer in it.It is heated to melt the ice.
Observation –
i)
Temperature of ice remains 0⁰C on melting.
ii)
Heat is needed to change ice at 0⁰C to water at 0⁰C.
- Ice at 0⁰C is more cooler than water at 0⁰C.
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| Activity 2 |
Activity
3:-
Drying
wet cloths
Observation:–
i)
Dry faster under sun.
ii)
Spread out wet cloth dries up faster than
folded one.
iii)
In rainy reason , drying takes time.
iv)
Cloth dries under fan too.
Conclusion:-
Rate
of evaporation depends upon:-
i)
Temperature of liquid
ii)
Area of surface exposed
iii)
Presence of humidity
iv)
Blow of air above liquid.
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| Activity 3 |
