How do solids and gases change state?
By sublimation: The change from a solid state directly into
 a gas is called sublimation. As the particles of solid dry ice
gain energy their motion completely overcomes the attraction
 between the particles, and the particles escape into the air as gas.

By deposition: is the change in state from

 a gas directly to a solid. Deposition

 is the process by wich ice crystals form in clouds.

 How do liquids and gases change state?
By evaporation:
As a liquid is warmed, its particles gain energy. Some particles gain enough
 energy that they escape from the surface of the liquid and become gas.

By boiling: A rapid change from a liquid to a gas. 

This changes takes place throughout a liquid, not just at the surface.

 The specific temperaturenat which this

 occurs in a liquid is called boiling point.

By condensation: the attraction bbetween particle

s overcomes the speedof their motion, and a liquid forms.

 This change is called condensation. 

 How do solids and liquids change states?
 By freezing: the change in state in wich a liquid becomes a solid is called freezing. The temperature at wich a liquid substance changes into a solid is the liquid´s freezing point.

By melting: the particles are able to slide past one another. 

This change is called melting.

 What happens when substances change state?
 Ice, liquid water and water vapor are different states of the same substance

 Shape up:
All solid substances has a definite shape and volume. The particles in a solid are fixed positions and are close together. A solid can´t easily change in shape or volume. You can change the shape of a solid by breking it into pieces.

the water would take the shape of the container. The water would have the same volume as the container. All liquids have a definitive volume but no definite shape. The particles in a liquid are close together, but they are not tightly attached to one another. 

Gases do not have a definite volume or shape. The particles in a gas are very far apart compared to the particles in a solid or a liquid. The amount of space between the particles in a gas can change more easily.

Gas: it doesn´t have a definite volume or shape. Its particles move freely.

Liquid: a substance that has a definite volume but not shape, it adopts the shape of its container. The particles are clase together but not in a fixed position so they can move from one place to another.

Solid: a substance with a definite volume and shape in which the particles vibrate in a fixed pocition.

Kinetic theory of matter: All matter is made of atoms or groups of atoms that are in constant movement.

Colloids: a mixture that falls between suspensions and solutions. The particles of a colloid are spread throughout a liquid or gas like in a suspension but unlike a suspension colloid particles are small and don´t settle out quickly.

Solutions: an homogeneous mixture in which one substance is dissolved in another substance.

Suspensions: an heterogeneous mixture in which the particles of a material are spread throughout a liquid or gas but too large to stay mixed without being stirred or shaken.

¿How can mixtures be classified?

As Heterogeneous: A mixture without an uniform composition.

As Homogeneous: A mixture in which the substances are evenly spread throughout.

How can you classify compounds?

By their pH: You can classify a compound as acid, basic or neutral measuring a value called pH. You should never touch, taste or smell a chemical to classify if because many acids can damage your body.

As organic or inorganic: An organic compound has carbon and hydrogen, an inorganic compound doesn´t have carbon nor hydrogen. Strawberries are organic.

By their role in our body: Organic compounds that are made by living things are called biochemicals. They are divided in carbohydrates, lipids, proteins, and nucleic acids. Carbohidrates are used as source of energy and include source of energy, they include sugars, starches and fiber. Lipids store exess energy in the body, they include fats, oils and waxes. Proteins regulate chemical activities. Nucleic acids contain genetic information.

How can you classify an element?
Differences in physical and chemical properties allow us to classify elements. By knowing the category to which category an element belogs to, you can predict some of its properties. Elements are classified in the periodic table of elements.

Pure substances: a substance with definite physical and chemical properties is a pure substance. They are made up of one type of particle and cannot be formed or broken down by physical changes. Elements and compounds are pure substances, for example copper is a pure substance.

Mixture: a variety of elements and compounds that aren´t chemically combined with each other.

Compound: a compound is made by atoms of different kind chemically combined.

Element: elements are made by one or more atoms of the same kind.

Atoms: the smallest unit of an element that mantains the properties of an element.

Lesson 4: Pure substances and mixtures