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I.P.S.I.A “ Zanussi” di Pordenone. Le Science in pillole O Appunti di scienze A cura delle insegnanti Allida De Candido e Cristiana Ziraldo. Summary. Home. Subject Area: Science Class Level and Course Title: first Class / Science of Earth Unit of Study: States of Matter.
Le Science in pillole
Appunti di scienze
A cura delle insegnanti
Allida De Candido e Cristiana Ziraldo
Class Level and Course Title: first Class / Science of Earth
Unit of Study: States of MatterStates of matter
Matter is anything that takes up space and has weight
Matter is anything that takes up space and has mass or weight.
Matter exists in three forms or states - solid, liquid and gas.
Solids can be
soft or hard
Can you think of something on the Earth that is hard?
Liquids can be
On the Earth
Gas can be
Particles in a solid have fixed position.
They are close together.
If they are positioned in a regular structure they may
The forces holding them in position are strong, so solids have their own shape.
At 0 K (-273°C) the particles are stationary.
At temperature above 0 K the particles vibrate but
cannot move from their positions.
As the temperature increases the vibrations become
The distances between gas are relatively large.
Therefore they are almost completely free of forces and so spread out and fill any container into which they are placed.
They are moving around at high speeds (approx. 500 m/sec at room temperature).
Gases diffuse (spread out and mix) more quickly than liquids.
The directions in which they move have no pattern: they are random motions (speed and direction).
The gas particles inside this container are continually
bouncingoff the sides. It is these collisions with the sides of the container that create the pressure inside the container.
There are several factors that will affects the size of the pressure in a gas.
If the volume of the container is decreased, the particles will have less distance to travel between collisions.
There will therefore be more collisions per second, i.e. the pressure will increase.
If more gas particles are pushed into the container there will be more frequent collisions and so the pressure will increase.
If the temperature of a gas is increased its particles will move faster, there will be more collisions each second and there will again be an increase in pressure.
To sum up
In the daily lives, there are a variety of matter in the different states.
To be able to classify and describe the changes of state
To know haw matter changes and what causes matter to change
Changes of State of Matter There are different changes that can take place. Water, for example, can change from water to ice, which is calledfreezing.
Freezing is what happens whena liquid changes to a solid.
Water can change from ice to water, which is calledmelting.
Melting is what happens when a solid changes to a liquid.
Water can also change from a water to steam, which is called evaporation.
Evaporation is what happens when a liquid changes to agas. Water can change from steam back to water, which is called condensation.
Condensation occurs when gas changes into a liquid.
There are some substances which can go from being a solid, directly to the gas state, which is called sublimation.
Solid carbon dioxide, commonly known as Dry Ice, bypasses the liquid state altogether when it changes to a gas.
The last change of state is matter going from a gas, directly to the solid state, which is called deposition.
Water vapours in the air during winter fall in the form of snow,
Energy is either lost or gained during a change of state.
* When energy is applied to a solid, the tightly packed particles of matter begin to move around, flowing over each other. The result is the movement of liquid. The shape becomes indefinite. The volume, however, does not change, because the particles are still part of one another.
* When energy is applied to a liquid, the particles that make up a liquid, begin to move about so rapidly, that they can no longer hold themselves together. The result is the movement of a gas. The shape is indefinite, and the volume becomes indefinite.
The reverse happens to gas when energy is taken away. Water vapour, for example begins to liquefy as it cools. Remember the cool mornings when fog is dense and close to the ground? What happens? Dewdrops form. The water vapours in the air cool to form liquid drops on grass.
* When energy is taken away from liquid, the particles in the liquid slow down to low movement. The resulting solid, has definite shape and definite volume.
1) When a solid changes into a liquid, it is called ......
2) When a solid changes directly into a gas, it is called......
3) When a gas changes into a liquid, it is called ......
4) Matter in a solid state has . . . . . volume and . . . . . .
____ no definite _____ no definite
____ a definite ______ a definite
____ a definite ______ no definite
5) The states of matter are the following:
solids, liquids, gases, plastics.
6) States are also known as ?
7) Which phase of matter does not take the shape of
the container it is in?
9) When solids reach their melting point they
10) What happens when a gas reaches condensation
it becomes a solid
it becomes a liquid
11) What is evaporation?
When liquids turn into vapour
When solids turn into vapour
12) What state / phase can fit into any container of any
size and any shape?
liquid and solid
13) Gas and vapour means the same.
14) Which state can hold their own shape?
try to change its shape?
16) When a liquid changes into a solid, it is called ......
17) Solidification is when a gas changes into a solid.
18) Matter in a ...... has a ...... volume and ...... shape.
gaseous state ___ no definite ___ no definite
liquid state _____ no definite ___ definite
solid state _____ no definite ___ no definite
19) When water freezes or when water becomes a vapour
is it still the substance: water?
a) yes b) no
20) Pick the correct statement:
a)Solids become gases at their melting points
b)Solids become liquids at their melting points