Subject of Chemistry

Fundamentals of the material world: atoms and temperatures

All objects of living and inanimate nature consist of basic particles — atoms. The form in which they exist depends directly on temperature conditions.

For example, in a high-temperature environment such as the Sun (which is a huge incandescent gas sphere with a diameter of more than a million kilometers), the surface temperature reaches approximately 5800°C. Under such extreme conditions, matter exists as "solar gas." The atoms within it move randomly and at a colossal speed. It is this high kinetic energy that prevents them from combining with each other.

However, as the temperature drops, the physical picture changes. When matter cools to 4500–4000°C, the speed of atom movement decreases. This allows them to come into contact and form stable bonds — thus molecules appear.

Chemical interaction on Earth

The conditions on the surface of our planet are such that practically all atoms are not in a free state, but in a bound state. They form substances that can exist in solid, liquid, and gaseous forms. The process of atoms connecting with each other constitutes chemical interaction.

It can be said with certainty that absolutely everything existing on Earth is a direct result of such interactions. The terrestrial material world has two most important characteristics:

1. Diversity — ranging from the simplest minerals to complex living organisms and artificially synthesized objects.
2. Variability — matter is continuously transforming, which we observe in the form of biological cycles of plants or in the processes of metal corrosion (rusting).

What chemistry actually studies

Substances are the object of study of many disciplines, including physics, mechanics, materials science, and pharmacology. But chemistry has its own unique specialization. The main difference of chemistry is that it gives priority to studying the transformations of substances — both upon contact with each other and when external conditions change.

Chemistry investigates the factors on which chemical properties depend (i.e., those properties that manifest upon the formation of new products):

• Composition of the substance.
• Internal structure.
• External influences.

The functions of chemical science include discovering new substances, investigating their properties, selecting the most valuable compounds for practical use, and developing methods for their mass production. This makes it possible to provide humanity with medicines, energy carriers, and industrial materials. Moreover, chemical processes form the very basis of vital activity in the plant and animal kingdoms.

From craft to science: alchemy and modern theory

In ancient times, chemistry was purely applied in nature: artisans empirically obtained metals, dyes, glass, cosmetics, and the first medicines. In the Middle Ages, alchemy emerged. Its main driving force was the high value of gold as a source of power. Alchemists put forward the hypothesis about the possibility of targeted conversion of cheap metals into gold and searched for the mythical philosopher's stone.

As a science, alchemy proved false because the task of metal transmutation is insoluble by chemical methods. However, there was a crucial positive outcome: in the course of continuous empirical experiments, alchemists discovered a huge number of new substances.

Modern science aims not just to create useful products, but also to understand the causes of phenomena through experiments and calculations. Nevertheless, chemical theories do not yet possess the same absolute predictive accuracy as the laws of mechanics (which can predict the movement of celestial bodies years in advance). In chemistry, many parameters still cannot be predicted. A classical example: the solubility of a specific substance in water cannot be calculated purely theoretically — it can be determined only experimentally.

Briefly: answers to topical questions

Class and exam questions

What else to study on this topic

• Types of chemical bonds and mechanisms of molecular formation
• Influence of temperature and pressure on the rate of chemical reactions
• Fundamentals of pharmacological chemistry: how drugs are created
• Empirical methods in chemistry: solubility and methods for its determination

Other topics in the section "Chapter 1. Substances. Properties and Structure"

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.