Who knows the formula of water since school days? Of course, everything. It is likely that from the entire course of chemistry, for many who then do not study it specializedly, the only thing left is the knowledge of what the formula H2O stands for. But now we will try to understand as much as possible in detail and deeply what is water? What are its main properties and why exactly without it life on planet Earth is impossible.
Water as a substance
The water molecule, as we know, consists of one oxygen atom and two hydrogen atoms. Its formula is written like this: H2O. This substance can have three states: solid - in the form of ice, gaseous - in the form of steam, and liquid - as a substance without color, taste and smell. By the way, this is the only substance on the planet that can exist in all three states simultaneously in natural conditions. For example: at the poles of the Earth - ice, in the oceans - water, and evaporation under the sun's rays is steam. In this sense, water is anomalous.
Also, water is the most common substance on ourplanet. It covers the surface of planet Earth by almost seventy percent - these are oceans, and numerous rivers with lakes, and glaciers. Most of the water on the planet is s alty. It is unsuitable for drinking and for farming. Fresh water makes up only two and a half percent of the total amount of water on the planet.
Water is a very strong and high-quality solvent. Due to this, chemical reactions in water take place at a tremendous speed. This same property affects the metabolism in the human body. It is a well-known fact that the body of an adult is seventy percent water. In a child, this percentage is even higher. By old age, this figure drops from seventy to sixty percent. By the way, this feature of water clearly demonstrates that it is the basis of human life. The more water in the body - the he althier, more active and younger it is. Therefore, scientists and doctors of all countries tirelessly repeat that you need to drink a lot. It is water in its pure form, and not substitutes in the form of tea, coffee or other drinks.
Water shapes the climate on the planet, and this is not an exaggeration. Warm currents in the ocean heat entire continents. This is due to the fact that water absorbs a lot of solar heat, and then gives it away when it starts to cool. So it regulates the temperature on the planet. Many scientists say that the Earth would have cooled down and turned into stone long ago if it were not for the presence of so much water on the green planet.
Properties of water
Water has many very interesting properties.
For example, water is the most mobile substance after air. From the school course, many, for sure, remember such a thing as the water cycle in nature. For example: a stream evaporates under the influence of direct sunlight, turns into water vapor. Further, this steam is carried somewhere by the wind, collects in clouds, and even in thunderclouds and falls in the mountains in the form of snow, hail or rain. Further, from the mountains, the brook again runs down, partially evaporating. And so - in a circle - the cycle repeats millions of times.
Also, water has a very high heat capacity. It is because of this that water bodies, especially oceans, cool very slowly during the transition from a warm season or time of day to a cold one. Conversely, when the air temperature rises, the water heats up very slowly. Due to this, as mentioned above, water stabilizes the air temperature throughout our planet.
After mercury, water has the highest surface tension. It is impossible not to notice that a drop accidentally spilled on a flat surface sometimes becomes an impressive speck. This shows the ductility of water. Another property manifests itself when the temperature drops to four degrees. As soon as the water cools to this mark, it becomes lighter. Therefore, ice always floats on the surface of the water and freezes in a crust, covering rivers and lakes. Thanks to this, fish do not freeze in water bodies that freeze in winter.
Water as a conductor of electricity
First, you should learn about what electrical conductivity is (including water). Electrical conductivity is the ability of aor substances conduct electricity through themselves. Accordingly, the electrical conductivity of water is the ability of water to conduct current. This ability directly depends on the amount of s alts and other impurities in the liquid. For example, the electrical conductivity of distilled water is almost minimized due to the fact that such water is purified from various additives that are so necessary for good electrical conductivity. An excellent current conductor is sea water, where the concentration of s alts is very high. The electrical conductivity also depends on the temperature of the water. The higher the temperature, the greater the electrical conductivity of water. This pattern was revealed thanks to the multiple experiments of physicists.
Measuring the electrical conductivity of water
There is such a term - conductometry. This is the name of one of the methods of electrochemical analysis based on the electrical conductivity of solutions. This method is used to determine the concentration in solutions of s alts or acids, as well as to control the composition of some industrial solutions. Water has amphoteric properties. That is, depending on the conditions, it is able to exhibit both acidic and basic properties - to act both as an acid and as a base.
The device used for this analysis has a very similar name - a conductometer. Using a conductometer, the electrical conductivity of electrolytes in a solution is measured, the analysis of which is being carried out. Perhaps it is worth explaining another term - electrolyte. This is a substance that, when dissolved or melted,breaks down into ions, due to which an electric current is subsequently conducted. An ion is an electrically charged particle. Actually, the conductometer, taking as a basis certain units of electrical conductivity of water, determines its electrical conductivity. That is, it determines the electrical conductivity of a specific volume of water taken as the initial unit.
Even before the beginning of the seventies of the last century, the unit of measure "mo" was used to indicate the conductivity of electricity, it was a derivative of another quantity - Ohm, which is the main unit of resistance. Electrical conductivity is a quantity that is inversely proportional to resistance. Now it is measured in Siemens. This value got its name in honor of the physicist from Germany - Werner von Siemens.
Siemens
Siemens (can be denoted by both Cm and S) is the reciprocal of Ohm, which is a unit of electrical conductivity. One cm is equal to the electrical conductivity of any conductor whose resistance is 1 ohm. Expressed by Siemens through the formula:
Thermal conductivity of water
Now let's talk about what thermal conductivity is. Thermal conductivity is the ability of a substance to transfer thermal energy. The essence of the phenomenon lies in the fact that the kinetic energy of atoms and molecules, which determine the temperature of a given body or substance, is transferredanother body or substance during their interaction. In other words, thermal conductivity is heat exchange between bodies, substances, as well as between a body and a substance.
The thermal conductivity of water is also very high. People daily use this property of water without noticing it. For example, pouring cold water into a container and cooling drinks or foods in it. Cold water takes heat from the bottle, container, instead giving cold, the reverse reaction is also possible.
Now the same phenomenon can be easily imagined on a planetary scale. The ocean heats up during the summer, and then - with the onset of cold weather, it slowly cools down and gives up its heat to the air, thereby heating the continents. After cooling down during the winter, the ocean begins to warm up very slowly compared to the land and gives up its coolness to the continents languishing from the summer sun.
Density of water
It was said above that fish live in a pond in winter due to the fact that water freezes with a crust over their entire surface. We know that water begins to turn into ice at a temperature of zero degrees. Due to the fact that the density of water is greater than the density of ice, ice floats and freezes on the surface.
What is the redox properties of water
Also, under different conditions, water can be both an oxidizing agent and a reducing agent. That is, water, giving up its electrons, is positively charged and oxidized. Or it acquires electrons and is charged negatively, which means it is restored. In the first case, the water oxidizes and is called dead. She possessesvery powerful bactericidal properties, but you don’t need to drink it. In the second case, the water is alive. It invigorates, stimulates the body to recover, brings energy to the cells. The difference between these two properties of water is expressed in the term "redox potential".
What can water react with
Water is able to react with almost all substances that exist on Earth. The only thing is that for the occurrence of these reactions, you need to provide a suitable temperature and microclimate.
For example, at room temperature, water reacts well with metals such as sodium, potassium, barium - they are called active. Halogens are fluorine and chlorine. When heated, water reacts well with iron, magnesium, coal, methane.
With the help of various catalysts, water reacts with amides, esters of carboxylic acids. A catalyst is a substance that seems to push the components to a mutual reaction, accelerating it.
Is there water anywhere else but Earth?
So far, water has not been found on any planet in the solar system, except Earth. Yes, they assume its presence on the satellites of such giant planets as Jupiter, Saturn, Neptune and Uranus, but so far scientists do not have exact data. There is another hypothesis, not yet fully verified, about groundwater on the planet Mars and on the Earth's satellite - the Moon. Regarding Mars, a number of theories have been put forward that once there was an ocean on this planet, and its possible model was even designed by scientists.
Outside the solar system, there are many large and small planets, where, according to scientists, there may be water. But so far there is not the slightest way to be sure of this for sure.
How to use the thermal and electrical conductivity of water for practical purposes
Due to the fact that water has a high heat capacity, it is used in heating mains as a heat carrier. It provides heat transfer from the producer to the consumer. Many nuclear power plants also use water as an excellent coolant.
In medicine, ice is used for cooling, and steam is used for disinfection. Ice is also used in the catering system.
In many nuclear reactors, water is used as a moderator for a successful nuclear chain reaction.
Pressure water is used to split, break through and even cut rocks. This is actively used in the construction of tunnels, underground facilities, warehouses, subways.
Conclusion
It follows from the article that water in its properties and functions is the most irreplaceable and amazing substance on Earth. Does the life of a person or any other living being on Earth depend on water? Certainly yes. Does this substance contribute to human scientific activity? Yes. Does water have electrical conductivity, thermal conductivity and other useful properties? The answer is also yes. Another thing is that there is less and less water on Earth, and even more so clean water. And our task is to preserve and secure it (and, therefore, all of us) fromdisappearance.
