Understanding Matter: States, Mixtures, and Synthetic Materials
Matter is formed by particles. A model represents how matter behaves and is based on two key ideas:
- Matter is formed by tiny particles.
- These particles that make up matter are in constant movement.
States of Matter
Solid
Particles are tightly bound and do not produce any movement; they only vibrate.
Liquid
Particles are less united and less ordered, allowing them to move.
Gas
Particles are together but can move freely.
Changes of State
If the temperature changes, a substance can transition from one state to another.
Solid to Liquid (Melting/Fusion)
The process by which a solid turns into a liquid is called fusion. The reverse process is called solidification. The melting and solidification temperatures of a substance are the same.
Liquid to Gas (Vaporization/Condensation)
The step from liquid to gas is called vaporization, which can occur through boiling or evaporation. The inverse process, from gas to liquid, is called condensation.
Melting and Boiling Points
Each substance has specific properties, including temperatures at which changes of state occur.
When a solid is heated, particles gain energy and move faster until they separate, transforming into a liquid. If heating continues, the particles of the liquid separate widely from each other and turn into gas.
On the surface of liquids, any particle can have enough energy to escape, allowing liquids to evaporate at any temperature.
Mixtures and Solutions
A material with a uniform appearance is called homogeneous. It presents a uniform appearance, and its parts cannot be distinguished. Mixtures that do not have a uniform appearance are called heterogeneous mixtures.
Solutions are homogeneous mixtures formed by various substances. The simplest solutions are composed of two components:
- Solvent: The component present in the largest amount.
- Solute: The component present in a minority.
Solutions can be liquid, gas, or solid (such as metal alloys).
Separation of Components of a Mixture
Filtration
Separates a solid from a liquid in which it is not soluble. A paper filter allows the liquid to pass through while retaining the solid particles.
Decanting
Used to separate different liquids that are not soluble in each other. A decanting funnel regulates the separation.
Distillation
Used to separate two or more liquids soluble in each other. The mixture is boiled in a flask, and the vapors are condensed in a cooling tube. The various components are separated according to their boiling temperatures.
Pure Substances
A pure substance has specific properties that characterize it and serve to distinguish it.
- Chemical compounds are pure substances that can be decomposed into simpler substances through chemical methods.
- Elements are chemical substances that cannot be decomposed into other simpler substances.
Synthetic Materials
Plastics
Materials widely used in today’s society, derived from petroleum. Their properties include:
- Very lightweight but with good strength and wear resistance.
- Impermeable to water.
- Unchanged by many chemical substances.
- Do not rust or rot.
- Very hygienic.
- Easily molded when heated.
- Good thermal and electrical insulation.
Glass
A hard yet fragile material, transparent and insulating to electricity and heat. It does not react with many substances, is resistant to abrupt changes in temperature, and can break.
Fiberglass
A fiber material obtained by passing molten glass through a very fine piece with holes. It is a thermal insulator and does not rust.
Moldable optical fiber is manufactured through fiberglass and is able to steer light.
Carbon Fiber
A plastic material made of carbon fiber, reinforced, elastic, and very strong.
States of Matter
The different ways in which matter may present itself are known as physical states:
- Solid
- Liquid
- Gas
Features
- Solids: Have their own shape and fixed volume.
- Liquids: Do not hold their own shape but maintain a fixed volume and can flow.
- Gases: Have no proper form, can flow, and have no fixed volume.