Chemicals and human health. What are the substances? What are the substances in nature? Definition of the word "substance"
They give simple examples and explain what substances are.
Definition of the word "substance"
Simply put, a substance can be called everything that any body consists of. In older classes, matter is called the matter that makes up the physical body, and it has certain physical and chemical properties. A substance is also called a set of atoms or molecules that are in a certain state of aggregation. All substances constitute a certain body. We mostly intersect with its solid state, in which the particles can hold their shape and not flow. But it can contain liquid and gaseous substances. That is, what are the substances and bodies in terms of origin? Bodies can be created by nature and through human intervention.
An ordinary stone lying in the mountains was created by nature, and a mineral grown in a laboratory, inserted into a frame, is already the work of man, an artificial body. But all substances that are simple (we will talk about this later) are created by nature. People could already create their various mixtures, but the main basis was laid by it. Answering the question of what substances and bodies are, we can say that they are divided into natural and artificially created.
according to the interaction of particles, or according to the state of aggregation
The substance is divided into several groups according to different characteristics. So, it is possible to characterize what substances are depending on the interaction of particles. Strong particle interaction is characteristic of solids. Gases are characterized by an almost absolute absence of interaction. located in the middle between solid and gaseous material - the particles interact, but not as strongly as in solids. This property is explained by the fact that there are gaps between the particles that make up the material, and in solid materials these gaps are very small, and in gaseous they are huge. Substances are divided into the same groups by the kinetic energy present in the particles and the potential energy of interaction. In liquids, these energies are practically comparable. In solids, in gases, on the contrary, the kinetic one prevails. The answer to the question of what substances are in nature can be any of these options. Any of the above states or characteristics are found both in objects created by nature and in things that have appeared as a result of human activity.
Interestingly, one substance can be in different states. So, the simplest example is water. At low temperatures, the liquid turns into ice, into a solid. When the temperature rises to 100 degrees Celsius and above, water from a liquid turns into a gas.
Separation of substances in chemical terms
In chemistry, it is customary to distribute substances into two main categories - these are individual substances and mixtures. That is, what are the substances in chemistry? Previously pure, but now individual substances are those that cannot be divided into simpler parts, they are indivisible. Mixtures are materials that have several components in their composition. In fact, it turns out that a mixture can consist of several individual substances.
In turn, the individual substance can be simple or complex. Simple is a substance that consists of atoms of only one chemical element, complex - of several: two or more. Simple is also called elementary, and - connection.
As mentioned earlier, the mixture consists of several and in this respect they are divided into homogeneous and heterogeneous, or solutions and mechanical mixtures. A simple example of what kind of solution type substances are is ordinary tea. It consists of two or three components - water, tea leaves and sugar. Sugar is uniformly distributed throughout the water and cannot be detected except by taste.
But if a lot of sugar is poured into tea, and it does not dissolve completely, then it will already be a mechanical mixture. Some of the sugar will dissolve, and some will lie at the bottom. Because of this, the samples of tea in the upper layers will be slightly different, at the bottom it will be sweeter, and at the top - less. The mixture will also be an elementary mixture of sand and sugar. The particles will be jumbled and difficult to separate, but they will retain their properties rather than creating new compounds.
Organic and inorganic substances
The question of what substances are in nature can be answered: organic is any substance that can be formed without the participation of a living organism and constitutes inanimate nature. Organic matter is diametrically opposed - it is formed only with the participation of a living organism and is part of this very living organism. again, there is water known to all, accessible and so necessary for life, as well as air, namely oxygen, various mineral salts. Organic substances include fats, carbohydrates, pigments, proteins. It's funny that the section on this type was made from the opinion of scientists about living beings as special organic compounds, and all other objects of inanimate nature were listed as inorganic. As it turned out later, there are a lot of inorganic substances in the human body, as, indeed, in the body of any animal on our planet.
A distinctive feature of organic substances can be considered that almost all of them contain carbon. Most inorganic substances have a high melting and boiling point, while organic substances do the opposite.
Separation according to fire regulations
Interestingly, when asked what substances and materials are, the firefighter will most likely answer - combustible and non-combustible. Between them there are still hardly flammable substances that can catch fire if there is constant exposure to the flame, but if the source is removed, it goes out. Accordingly, a combustible substance or material is capable of burning when exposed to a source, and may even self-ignite. A non-flammable substance cannot burn in air. All children will learn more about this in the lessons of labor protection or life safety.
Impact on the human body
All substances found in nature can be divided into dangerous and safe. The dangerous ones can be considered those that have already been mentioned above - burning ones. What is the danger? They can harm the health of a person who will be in the fire. This will be a physical effect on the skin: burns or exposure to internal organs through the respiratory tract. By the way, in the same way, the negative impact occurs during smoking. Smoking not only tobacco products, which contain many known substances harmful to the human body, but also drugs.
What are the drugs
Not all drugs are taken by smoking, some are injected into a vein, inhaled as a powder through the nose, or eaten as a pill. But all of them have side effects, despite the fact that before this they could bring a feeling of joy and happiness, high spirits, or some other positive effect. All these effects are short-term, but everyone knows that the harm from them will definitely last much longer.
conclusions
If you ask a child: "Tell me what substances and materials are, give examples," then he will have many different answers. It is important to make it clear to the student that the same substance can belong to several types that were listed above, differ in certain characteristics. From a very young age, knowledge of what substances are will expand as the school sciences are studied.
Through the veil of time, I remember myself as a small child: how inquisitively I studied the world around me, trying to understand what it consists of. I remember the first lessons in physics and chemistry, where I first learned that "substance" is not just a word, but a term. And today I myself can talk about substances and materials.
Variety of substances in nature
We can say that everything that surrounds us is substances. All items are made from some material. And all this wealth has different properties. But, nevertheless, it is possible to classify substances by highlighting their main states. They are solid, liquid and gaseous.
We can see all three states in the example of water, which is solid (ice), liquid and gaseous (steam). Each substance, if the right conditions are created, can appear before us in any capacity.
In chemical science, substances are divided into organic and inorganic. Air, stone, the same water - these are examples of inorganic substances.
And everything that appears in the process of life is called organic matter.
And substances are simple (elementary) and complex (mixture or solution). For example, cocoa is a solution.
Here are some examples of different substances:
- gunpowder (combustible substance);
- protein, carbohydrate (organic matter);
- granite (solid).
What are the materials
Sometimes between the concepts of "material" and "substance" you can put an equal sign or call them synonyms.
But I would say that it is more customary to call a mixture of different substances a material. People use materials to create objects, parts, food and the like.
A wooden block can be called a material, from which a carpenter will make a stool or asphalt, which is used to lay a new highway.
Raw materials that a person has learned to extract (ore, oil) can also be called a material.
And they are also auxiliary and consumables, for example, glue or autol.
In science, there is a whole section that studies the properties and characteristics of materials. It's called materials science.
Throughout life, we learn about new substances and materials.
As you know, all substances can be divided into two large categories - mineral and organic. Many examples of inorganic or mineral substances can be cited: salt, soda, potassium. But what types of connections fall into the second category? Organic substances are present in any living organism.
Squirrels
The most important example of organic substances are proteins. They include nitrogen, hydrogen and oxygen. In addition to them, sometimes sulfur atoms can also be found in some proteins.
Proteins are among the most important organic compounds and they are the most commonly found in nature. Unlike other compounds, proteins have certain characteristic features. Their main property is a huge molecular weight. For example, the molecular weight of an alcohol atom is 46, benzene is 78, and hemoglobin is 152,000. Compared to the molecules of other substances, proteins are real giants containing thousands of atoms. Sometimes biologists call them macromolecules.
Proteins are the most complex of all organic structures. They belong to the class of polymers. If you look at a polymer molecule under a microscope, you can see that it is a chain consisting of simpler structures. They are called monomers and are repeated many times in polymers.
In addition to proteins, there are a large number of polymers - rubber, cellulose, as well as ordinary starch. Also, a lot of polymers were created by human hands - nylon, lavsan, polyethylene.
Protein formation
How are proteins formed? They are an example of organic substances whose composition in living organisms is determined by the genetic code. In their synthesis, in the overwhelming majority of cases, various combinations are used.
Also, new amino acids can be formed already when the protein begins to function in the cell. At the same time, only alpha-amino acids are found in it. The primary structure of the described substance is determined by the sequence of residues of amino acid compounds. And in most cases, the polypeptide chain, during the formation of a protein, twists into a helix, the turns of which are located closely to each other. As a result of the formation of hydrogen compounds, it has a fairly strong structure.
Fats
Fats are another example of organic matter. A person knows many types of fats: butter, beef and fish fat, vegetable oils. In large quantities, fats are formed in the seeds of plants. If a peeled sunflower seed is placed on a sheet of paper and pressed down, an oily stain will remain on the sheet.
Carbohydrates
No less important in wildlife are carbohydrates. They are found in all plant organs. Carbohydrates include sugar, starch, and fiber. They are rich in potato tubers, banana fruits. It is very easy to detect starch in potatoes. When reacted with iodine, this carbohydrate turns blue. You can verify this by dropping a little iodine on a potato slice.
Sugars are also easy to spot - they all taste sweet. Many carbohydrates of this class are found in the fruits of grapes, watermelons, melons, apple trees. They are examples of organic substances that are also produced under artificial conditions. For example, sugar is extracted from sugar cane.
How are carbohydrates formed in nature? The simplest example is the process of photosynthesis. Carbohydrates are organic substances that contain a chain of several carbon atoms. They also contain several hydroxyl groups. During photosynthesis, inorganic sugars are formed from carbon monoxide and sulfur.
Cellulose
Fiber is another example of organic matter. Most of it is found in cotton seeds, as well as plant stems and their leaves. Fiber consists of linear polymers, its molecular weight ranges from 500 thousand to 2 million.
In its pure form, it is a substance that has no smell, taste and color. It is used in the manufacture of photographic film, cellophane, explosives. In the human body, fiber is not absorbed, but it is a necessary part of the diet, as it stimulates the work of the stomach and intestines.
Substances organic and inorganic
You can give many examples of the formation of organic and second always come from minerals - inanimate which are formed in the depths of the earth. They are also part of various rocks.
Under natural conditions, inorganic substances are formed in the process of destruction of minerals or organic substances. On the other hand, organic substances are constantly formed from minerals. For example, plants absorb water with compounds dissolved in it, which subsequently move from one category to another. Living organisms use mainly organic matter for food.
Causes of Diversity
Often schoolchildren or students need to answer the question of what are the reasons for the diversity of organic substances. The main factor is that carbon atoms are interconnected using two types of bonds - simple and multiple. They can also form chains. Another reason is the variety of different chemical elements that are included in organic matter. In addition, diversity is also due to allotropy - the phenomenon of the existence of the same element in various compounds.
How are inorganic substances formed? Natural and synthetic organic substances and their examples are studied both in high school and in specialized higher educational institutions. The formation of inorganic substances is not as complex a process as the formation of proteins or carbohydrates. For example, people have been extracting soda from soda lakes since time immemorial. In 1791, the chemist Nicolas Leblanc suggested synthesizing it in the laboratory using chalk, salt, and sulfuric acid. Once upon a time, soda, which is familiar to everyone today, was a rather expensive product. To carry out the experiment, it was necessary to ignite common salt together with acid, and then ignite the resulting sulfate together with limestone and charcoal.
Another is potassium permanganate, or potassium permanganate. This substance is obtained in industrial conditions. The formation process consists in the electrolysis of a potassium hydroxide solution and a manganese anode. In this case, the anode gradually dissolves with the formation of a violet solution - this is the well-known potassium permanganate.
2014-06-04Causes of a wide variety of substances. Thanks to the existence of more than 100 types of atoms and their ability to combine with each other in different quantities and sequences, millions of substances were formed. Among them are substances of natural origin. These are water, oxygen, oil, starch, sucrose and many others.
Thanks to advances in chemistry, it has become possible to create new substances even with predetermined properties. Such substances are also known to you. This is polyethylene, the vast majority of medicines, artificial rubber - the main substance in the composition of rubber, from which bicycle and car tires are made. Since there are a lot of substances, there was a need to somehow divide them into separate groups.
Substances are divided into two groups - simple and complex.
simple substances. There are substances in the formation of which atoms of only one type, that is, one chemical element, participate. Let's use the reference table. 4 (see p. 39) and consider examples. From the atoms of the chemical element aluminum given in it, a simple substance aluminum is formed. This substance contains only aluminum atoms. Like aluminum, the simple substance iron is formed only from the atoms of one chemical element - iron. Please note that the names of substances are usually written with a lowercase letter, and chemical elements - with a capital letter.
Substances formed by atoms of only one chemical element are called simple.
Oxygen is also a simple substance. However, this simple substance differs from aluminum and iron in that the oxygen atoms from which it is formed are connected two in one molecule. The main substance in the composition of the Sun is hydrogen. This is a simple substance, the molecules of which consist of two hydrogen atoms.
Simple substances are composed of either atoms or molecules. Molecules of simple substances formed from two or more atoms of one chemical element.
Complex substances. There are hundreds of simple substances, while there are millions of complex ones. They are made up of atoms of different elements. Indeed, the molecule of the complex substance of water contains hydrogen and oxygen atoms. Methane is made up of hydrogen and carbon atoms. Note that the molecules of both substances contain hydrogen atoms. A water molecule has one oxygen atom, but a methane molecule has one carbon atom.
Such a small difference in the composition of molecules and such a big difference in properties! Methane is a flammable substance, water does not burn and is used to extinguish fires.
The subsequent division of substances into groups is the division into organic and inorganic substances.
organic matter. The name of this group of substances comes from the word organism and refers to complex substances that were first obtained from organisms.
Today, more than 10 million organic substances are known, and not all of them are of natural origin. Examples of organic substances are proteins, fats, carbohydrates, which are rich in food (Fig. 20).
Many organic substances were created by man in laboratories. But the very name "organic matter" has been preserved. Now it extends to almost all complex substances containing carbon atoms.
Organic substances are complex substances whose molecules contain carbon atoms.
inorganic substances. The remaining complex substances that are not related to organic are called inorganic substances. All simple substances are inorganic. Inorganic substances are carbon dioxide, baking soda and some others.
In the bodies of inanimate nature, inorganic substances predominate, in the bodies of living nature, most substances are organic. On fig. 21 depicts bodies of inanimate nature and man-made bodies. They are formed either from inorganic substances (Fig. 21, a-d), or made from organic substances of natural origin artificially created by man (Fig. 21, d-f).
One sucrose molecule consists of 12 carbon atoms, 22 hydrogen atoms, 11 oxygen atoms. The composition of its molecule is denoted by the notation C12H22O11. When burned, charring) sucrose turns black. This is because the sucrose molecule decomposes into a simple substance carbon (it has a black color) and a complex substance water.
Be a conservationist
Organic materials (polyethylene) are used to make a variety of packaging materials, such as lawn water bottles, bags, and disposable tableware. They are strong, light, but not subject to destruction in nature, and therefore pollute the environment. Especially harmful is the burning of these products, since during their combustion toxic substances are formed.
Protect nature from such pollution - throw them into the fire of plastic products, collect them in specially designated places. Advise your relatives and friends to use biopackages, Bioware, which decompose over time without harming nature.
