The Particle Theory, States of Matter, Changes in States

Matter is anything that has mass and takes up space.

Anything around us and in the entire universe can be classified as either matter on energy.

The Particle Theory of Matter:

1. Matter is made up of tiny particles (Atoms & Molecules)
2. Particles of Matter are in constant motion.
3. Particles of Matter are held together by very strong electric forces
4. There are empty spaces between the particles of matter that are very large compared to the particles themselves.
5. Each substance has unique particles that are different from the particles of other substances
6. Temperature affects the speed of the particles. The higher the temperature, the faster the speed of the particles.

The particle theory of matter explains the following scientific phenomena:

Pure substance are homogeneous (one phase - one unique kind of particle)
Physical Changes - Melting, Evaporation, Sublimation, Dissolving.....
Characteristic Physical Properties - Density, Viscosity, Electrical & Thermal Conductivity

B. Properties: Information about a substance that describe it and that helps us identify it.
Characteristic Physical Properties - are physical properties that can be used to identify a substance because they never change. Example: The density of water is always 1.00 g/mL at room temperature.

C. States of Matter

Solid State Examples: rubber, iron, ice, chalk	Particles of a typical solid	1.SOLID STATE Particles of solids are held in place by strong electrostatic forces and are densely packed together. Particles of solids vibrate constantly due to their internal energy but they cannot move from one place to another. Particles of solids possess only vibrational energy.

Liquid State: Examples: alcohol, gasoline, oil, water	Particles of a typical liquid (What could the two different types of particles indicate?)	2. LIQUID STATE Particles of liquids are kept together by forces of attraction that are weaker than those of solid particles. Within the walls of the container they can move from place to place bumping into the sides of the container and into other particles. This type of energy is called translational energy. This energy gives a liquid the ability to flow and be poured and to spread when a liquid is spilled. Liquid particles also have vibrational energy.

Gaseous State: Examples: air, natural gas, carbon dioxide, steam	Brownian Motion demonstrating possible motion of tiny solids particles suspended in air (a gas) and indirectly showing the motion of particles of gases.	3. GAS STATE Particles of gases are "more rarefied" than either liquids or solids. This means that the forces of attraction that hold them together are very weak and that the spaces between them are much larger than the spaces between solid and liquid particles. Particles of gases can move from place to place within a container bumping against the walls of the container and against other particles. They rotate and vibrate at the same time. Particles of gases have rotational, translational and vibrational energy. This explains why they can escape from a container very easily and they can put pressure on the side of the container (example a balloon or a tire).

D. Physical Properties of Each State:

PROPERTY	SOLID	LIQUID	GAS
shape	fixed	same as container (indefinite)	same as container (indefinite)
volume	definite	definite	fills entire container (indefinite)
ability to flow	no	yes	yes
can be compressed	very slightly	very slightly	yes
volume change with heating	very small	small	large

E. Describing Matter

Intensive Properties: properties that do not depend on the amount of matter. Some examples are: colour, odour, density, melting point
Extensive Properties: properties that do depend on the amount of matter. Some examples are: mass and volume
Characteristic Physical: Properties: properties that are unique for each substance and are used to identify the substance itself.

F. How to Describe Matter (Qualitative & Quantitative Observations)

1. Physical State: solid, liquid, gas.
2. Colour: green, blue, yellow, black, reddish-brown, etc.
3. Odour: odourless, flowery, spicy, nauseating, etc.
4. Clarity: clear, cloudy, opaque.
5. Luster: shiny, dull.
6. Form: regular (crystalline), irregular (amorphous)
7. Texture: how does it feel? fine, coarse, smooth, waxy, etc.
8. Hardness: can it be scratched easily? scale from 1-10
(e.g. talcum powder-1, diamond-10)
9. Brittleness: can it break apart or shatter easily? brittle or flexible
10. Malleability: can it be bent and folded into different shapes? malleable or non-malleable
11. Ductility: can it be stretched out into a long wire? ductile or non-ductile
12. Viscosity: can the substance flow? viscous or non-viscous

G. Chemical Properties:

Properties of a substance that we observe when it reacts or does not react with other substances

iron rusts in moist air, gold does not
hydrogen burns in oxygen, but nitrogen does not
zinc reacts with acid, but glass does not

Physical & Chemical Changes

	Physical Change	Chemical Change
Definition	No new substance is produced Substance remains the same even with a change of state May require addition of energy Release of energy may occur	Final substance is substantially different than initial substance New substance is always produced Energy is usually released but may be required to get the change going
Properties	Outside may look different Inside remains the same Particles may be rearranged Forces of attraction between particles may be weaker or stronger	A new substance is produced The particles of the new substance do not resemble those of the old substance Internally, the substance produced is different than the old substances
Examples	Mixing sugar and water Ice melts into water Solid wax ==> Liquid wax	Vinegar and baking soda mix to form carbon dioxide Hydrochloric acid reacts with magnesium metal to form hydrogen gas

CHANGES OF STATES OF MATTER

When a state of matter gains or looses heat it undergoes a change.

A gain in heat is called an endothermic change. A loss in heat is called an exothermic change.

The table below summarizes the six changes of states that matter can undergo and tells you if heat is added or removed for the change to take place.

Change	From	To	Heat	Examples
Sublimation	solid	gas or vapour	added = endothermic	Moth crystals disappear when left in a closet for several days
Sublimation	gas or vapour	solid	removed = exothermic	frost forms on a car's windshield
Evaporation or vapourization	liquid	gas	added = endothermic	Rain dries up when the sun comes out
Melting or Liquefaction	solid	liquid	added = endothermic	An ice cube turns into water when left out of the freezer
Freezing or Solidification	liquid	solid	removed = exothermic	A bottle of water will turn into ice if left in the freezer
Condensation	gas or vapour	liquid	removed = exothermic	Drops of water form on the mirror when taking a hot shower

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