# Chemistry

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## Molecules in different states of matter

1) Different states of matter

Matter can exist in three different states: solid, liquid or gaseous.
It may also change of state:
From solid to liquid state (fusion or melting)
From liquid to gaseous state (vaporization)
From the gaseous to the liquid state (liquefaction or condensation)
From liquid to solid state (solidification or freezing)
From solid to gaseous state (sublimation)
From the gaseous to the solid state (deposition)

Although matter has different properties depending on its state:
Regardless of the state of a pure substance its molecules are identical.

Example: there is the same molecules of water in ice, in liquid water and water vapor.

2) Molecules in a solid

Schematic representation of molecules in a solid
(Molecules are symbolized by triangles)

In the solid state, molecules are very close to each other (almost stacked) and the space they occupy is small: they are said to have a compact arrangement.
Each molecule has a fixed position: it is an orderly arrangement.

The solid state is compact and ordered

3) Molecules in a liquid

Schematic representation of molecules in a liquid
(Molecules are symbolized by triangles)

L'état liquide est compact et désordonné.

Molecules are still very close to each other and form a compact arrangement. Nevertheless, the molecules are not stationary, they can move by sliding over each other and are slightly agitated: they are organized in a disorderly manner.

The liquid state is compact and disordered.

4)  Molécules in a gas

Schematic representation of molecules in a gas
(Molecules are symbolized by triangles)

The molecules are relatively far from each other and form a dispersed arrangement.
They are highly agitated and move very quickly in a disorderly manner.

The gaseous state is dispersed and disordered.

 Science class Mechanics lessons Water Water on Earth Changes of state in the nature: the water cycle Water in human body Test for water Properties of water in different states States of matter States of matter and its changes Boiling water Water: freezing and melting Changes of state: mass and volume Molecules in different states of matter Mixtures and solutions Heterogeneous mixtures Homogeneous mixtures Decantation Centrifugation Filtration Vaporization of water Distillation Chromatography Dissolving a solid in water Conservation of mass on dissolving Miscibility in water Mass and volume Volume and its units Measuring volume with a graduated cylinder Mass and its units Measuring the mass of a liquid Mass of a liter of water Volumetric mass density Air and atmosphere Earth's atmosphere protect us Pressure Atoms and molecules Molecules Molecules in mixtures and pure substances Molecules and states of matter Atoms Composition of molecules Constituents of the atoms The electrical neutrality of the atom Combustions Basics of combustion The combustion of carbon The combustion of butane Atoms and chemical reactions Chemical reactions Chemical equations Law of conservation of mass Chemical synthesis Metals Most common metals How to distinguish metals ? Corrosion of metals Electrical conductivity of solid materials Electrons and free electrons Electric current in metals Ions The conductivity of aqueous solutions Aqueous solutions and ions The direction of movement of ions Formation of ions Tests for ions Acidic and basic solutions pH of aqueous solutions Ions in acidic and basic solutions Dilution of acids and bases Composition of hydrochloric acid Chemical reaction between iron and hydrochloric acid Electrochemical cells and chemical energy Chemical reaction beteween a copper sulphate solution and zinc Copper sulfate and zinc battery Basics of electrochemical cell