The 15 physical and chemical properties of water

Water is undoubtedly one of the most important elements for us, to the point that all forms of life known up to now would not have been possible without their existence. It is part of each and every cell in our body, and we must drink frequently in order to survive.

The importance of water is capital, but beyond that the truth is that this element has different properties of scientific interest. That is why throughout this article we are going to see a brief exposition of some of the main physical and chemical properties of water.

• Related article: "The 9 differences between organic and inorganic compounds"

Physical and chemical properties of water

These are some of the properties of this element, some of them highly known by most people and others more technical and less taken into account.

1. It is colorless

Although when we see the sea or a river it may seem to us that the water may have a bluish-greenish or sometimes brownish color, this is due to the way it reflects light and because absorbs short wavelengths more easily

(With what is easier for our eyes to appear in bluish tones). However, we cannot perceive any color in it (unless it is mixed with another substance), being transparent to our eyes.

2. It has no taste or smell

Water is a substance that, unlike others, does not by itself have a specific taste or smell. In case the water tastes like something to us, it is because it has been adulterated in some way (for example adding flavorings) or because when it reaches us it has dragged particles of other elements (for example fruits or other foods, minerals, lime, plastic or pollutants).

3. Found in nature in all three states

There are many substances that are difficult to find in nature beyond a specific state of matter. However, in the case of water we can easily observe it in any of the states: the liquid water of the seas, rivers and rain, in gaseous form it can be observed as water vapor and in solid form it can be found as ice and snow.

4. Has a fixed transformation temperature

Although water can be mixed with other substances, the truth is that on a physical level we can contemplate how this element always evaporates or freezes at the same temperature, with a freezing point at 0ºC and a boiling point at 100ºC.

5. Composite and not element

Although water has been thought of as one of the basic elements since ancient times, the truth is that as its chemical formula indicates, H2O, we are not dealing with an element itself but with a compound in which each molecule is made up of two hydrogen atoms bonded to one atom of oxygen.

6. It is a solvent

Perhaps the word solvent is usually used at the popular level for other types of substances, but the truth is that water does act as such on a chemical level. And is that many substances dissolve in contact with H2O, being the water capable of changing its structure and properties.

In fact, it is an almost universal solvent for polar substances (that is, of those substances whose molecules have a positive pole at one end and a negative pole at the other), such as alcohol or you go out. Outside of laboratory chemical reactions, this property is essential to explain, for example, the functioning of living cells in our body.

• You may be interested: "The 5 types of chemical bonds: this is how matter is composed"

7. Has a neutral electrical charge

The atoms of a water molecule have a neutral electric charge, although this does not mean that its components do not have a charge, but that it is generally balanced. In general, each molecule consists of a dozen of both protons and electrons, in which the electrons are concentrated close to the oxygen. A) Yes, around oxygen the electrical charge tends to be somewhat more negative, while near hydrogen it is more positive.

8. Stable density

In the same way that freezing and boiling points are usually fixed, water is also characterized by maintaining a very stable density regardless of its environmental situation. Pure water without any other component (that is, distilled) has a density of 1 kg / l.

However, normally when in a liquid state at a temperature of around 20ºC, it has a density of 0.997-0.998 kg / l. In the case of ice, its density is usually 0.917 Kg / l.

9. Difficult to compress

Compressing a certain volume of water is highly complex (although not impossible), since this substance has a high level cohesion (that is, its molecules have a high capacity to remain united to each other due to the strong bond that perform).

10. It sticks

The water gets wet. This phrase, although it may seem obvious and even ridiculous, is talking about another of the physical properties of the liquid element: the ability to adhere to other surfaces and materials.

11. Low electrical conductivity

We have probably heard on occasion of someone who has been electrocuted or suffered a domestic accident when water comes into contact with an electrical element. As most of you know, these types of accidents are very real and dangerous.

However, it must be taken into account that the responsible party itself is not really the water, but the different salts and other components that it carries with it. In fact, distilled or pure water is not a conductor of electricity but an insulator, since it does not have free electrons that can conduct it.

Now, it is important to note that we are talking about distilled water in which there is nothing more than water molecules: the water we drink, with which we we shower and bathe and what we find in rivers and seas does conduct electricity since it contains a large amount of minerals and other components with potential driver.

12. Relatively neutral ph

Another characteristic of water is that in general and on average it tends to have a neutral or almost neutral pH, oscillating its pH between 6.5 and 8.5 (a totally neutral pH would be 7). This implies that generally water can be slightly acidic or slightly basic, but unless its degree of acidity is manipulated or mixed with other substances, pure water molecules are usually practically neutral.

13. Participate in multiple chemical reactions

Another aspect of water to take into account is its high level of interaction with other elements, such as a way that produces different chemical reactions and becomes part of different processes or substances.

For example, as we have already seen, it is capable of dissolving polar substances, as well as reacting with basic oxides and acids to form compounds such as calcium hydroxide or sulfuric acid. Also can generate various reactions on various types of metals, and participates in processes such as oxidation or the creation of hydrates.

14. High surface tension

This property refers to the force necessary to overcome the force of attraction between water molecules at surface level.

Its high value (in the case of water it has a value of 72.8 dyne / cm) generally means that when we are facing a Calm water surface tends to remain stable, something that makes it difficult to break its shape without force considerable. That is why leaves or other objects tend to float on top without generating an excessive alteration in the shape of the surface.

15. Regulate the temperature

Another interesting and well-known property of water is its ability to regulate temperature. And is that water is capable of retaining heat, something that causes it to cool more slowly than other substances. It also takes longer to heat up. We see an example in the effect that the sea has on the temperature of the coast, generally more moderate than in the interior.

Bibliographic references:

• Marín Galvín, R. (2010). Physical, chemical and biological characteristics of the waters. School of Industrial Organization. [On-line]. Available in: https://www.eoi.es/es/savia/publicaciones/19900/caracteristicas-fisicas-quimicas-y-biologicas-de-las-aguas.
• Marín Galvín, R.; Rodríguez Mellado, J.M. (1999). Physicochemistry of waters. Editorial Díaz de Santos.
• Félez Santafé, M. (2009). Current status of the status of biological purification. Explanation of the methods and evidence. Escola d'Enginlería de Barcelona- E.T. Industrial, specializing in Industrial Chemistry. Polytechnic University of Catalonia [Online]. Available in: http://hdl.handle.net/2099.1/6263.