Introduction - General Properties of Matter

Relevance of the Theme

The general properties of matter are indispensable tools for the understanding and study of any material system. They provide clues about how different substances interact with each other and with the environment around them. In other words, they provide the fundamental context for all chemical reactions, energy transformations, and natural phenomena that occur around us.

Without the knowledge of these general properties, the exact sciences, particularly Chemistry, would be ineffective, obscuring our perception of the world. After all, Chemistry is the central science! Everything, from matter itself to complex biological interactions, can be broken down into 'chemical pieces' that fit into this big puzzle.

Contextualization

Within the broad field of Chemistry, the general properties of matter are an intrinsic theme in the study of the structure and behavior of matter. They provide the basis for understanding more advanced concepts, such as atomic structure, chemical bonds, intermolecular interactions, and are crucial in solving Chemistry problems.

In the 1st year of High School, the study of the general properties of matter is the starting point for the entire Chemistry curriculum. Here, students begin to understand the world around them from a chemical perspective, learning to identify and describe the fundamental qualities of any substance.

This theme connects them with the basic principles of Chemistry, establishing the language and logic that will be used throughout the discipline. It is here that we take the first step to understand not only matter in its simplest forms, but also the complex interactions that give rise to the world we know.

Theoretical Development

• Mass and volume: Matter occupies space, and this occupation is measured by volume. Volume is a property that does not depend on the quantity of matter, therefore, it is considered an extensive property. Similarly, all matter has mass, and the quantity of matter is measured by this mass. Mass is also an extensive property.

• Impenetrability: Matter has the property of not mixing homogeneously with matter in a solid state, occupying the same space. That is, if an object already occupies space, another object cannot occupy exactly the same space at the same time. An example is water, which, when poured into a full glass, overflows.

• Inertia: Inertia is the property of matter to resist changes in its state of motion. In simple terms, 'an object at rest tends to stay at rest, and an object in motion tends to stay in motion at the same speed and in the same direction unless an external force is applied'.

• Elasticity: Elasticity is the property of matter to return to its original shape after the application of an external force that deforms it. For example, when you squeeze a rubber ball and then release it, it returns to its original shape.

• Compressibility and expansibility: These properties are related to the occupation of space by matter. Substances like air, for example, have the ability to be compressed into smaller volumes, while others, like water, cannot be significantly compressed.

Key Terms

• Matter: Everything that occupies space and has mass. It can be found in the form of solid, liquid, or gas.

• General properties of matter: Those that are common to all substances and are present in any physical state of matter. They are: mass, volume, impenetrability, inertia, elasticity, compressibility, and expansibility.

• Impenetrability: The impossibility of two bodies occupying the same place in space at the same time.

• Inertia: The resistance that a body offers to change its state of motion or rest.

• Elasticity: The property that some materials have to return to their original shape after being deformed.

• Compressibility and expansibility: The ability of a body to vary its volume depending on the force applied.

Examples and Cases

• Impenetrability in practice: When trying to dip a hand into a bucket full of water, you will encounter resistance because the water is occupying all the available space.

• Inertia in practice: When abruptly braking a car, you are pushed forward. This occurs due to inertia - your body was in motion and 'resists' sudden change.

• Elasticity in practice: When jumping on a trampoline, you experience elasticity when you are launched back into the air. The trampoline deforms under your weight, but then returns to its original shape and propels you upwards.

• Compressibility and expansibility in practice: Air is an example of a highly compressible substance. It can be compressed into much smaller spaces than it would normally occupy. On the other hand, water, despite being fluid, has only a slight compressibility.

These examples illustrate how the general properties of matter are present in our daily lives, often so naturally that we don't even realize it!

Partial Conclusions

• Unity in diversity: Despite the diversity of substances we find around us, they all have common general properties.

• Essentiality of general properties: It is not possible to understand the chemistry and physics of substances without understanding these general properties of matter. They are the basis for more complex concepts.

• Relationship between properties: The general properties of matter are not independent but interconnected. For example, an object's inertia depends on its mass, while compressibility is related to how the substance's particles are arranged.

Exercises

1. Describe what is meant by the impenetrability of matter and provide an example of how it manifests in everyday life.

2. Explain the concept of elasticity of matter and give an example where this property can be noticed.

3. List the factors that can influence the inertia of an object.