What is water and what are its properties? – Virtual Workers of America

We explain what water is and what the characteristics of this universal solvent are. Also, its state and properties changes.

Life on planet Earth originated in water.

What is water?

Water (H2O) is the most abundant substance on our planet. It is a molecule made up of two hydrogen atoms and one oxygen atom.The term “water” is generally used to refer to liquid water, while ““ice” is used to refer to water in a solid state and “steam” to refer to water in a gaseous state.

It is estimated that 71% of the earth’s surface is covered in watermost of this amount is in the oceans. Water also forms glaciers, ice caps, aquifers, permafrost (the layer of soil under the Earth’s surface that has remained frozen), underground water tables, rivers, lakes and streams. In addition, it is present in soil moisture, in the atmosphere and is the central component of the body of living beings.

The hydrosphere is made up of water that is below and above the solid surface of the Earth.and is made up of rivers, lakes, groundwater, ice, snow, oceans and seas.

Almost all theories on the origin of life on Earth suggest that life originated in water. Different studies have shown that life arose in surface waters or in the depths of the seas.

It is estimated that around 25% of the living species that inhabit planet Earth live in water, and bacteria are the most abundant living organisms in aquatic environments.

On planet Earth, water is maintained in continuous circulation through the hydrological cycle (or water cycle), which is the set of processes through which water circulates between the different compartments of the hydrosphere.

Physical properties of water

It is tasteless. Water does not have a specific flavor, so when ingested it will have the taste, in any case, of what is dissolved in it, such as sugar or salt.
It is transparent. Water does not have a specific color and allows light rays to pass through it. If it is mixed with another substance that does have color, then the mixture takes on the color of the dissolved substance.
It is odorless. The water has no smell. If it is mixed with another substance, the resulting mixture will have the odor of the dissolved substance.
It is a conductor of electricity. Water conducts electric current whenever it has chemical compounds dissolved in it, which dissociate into their ions (electrically charged particles) and generate the conduction of electric current. Pure water, without ions, does not conduct electric current.
It is magnetic. Pure liquid water is diamagnetic, that is, it is repelled by intense external magnetic fields.
It is incompressible. Liquid water is almost incompressible. Even at a depth of about 2 kilometers, subjected to 200 atm of pressure, water decreases its volume by only 1%.
Transmits sound. The propagation of sound in water occurs almost without attenuation, especially low frequencies. This property is used in the operation of sonar and is the basis of communication between cetaceans.
It has a high surface tension. The amount of energy required to increase the surface area of a liquid per unit area is called “surface tension.” Liquids with high surface tension, such as water, offer resistance to increasing their surface area. For this reason, insects can walk on water.

State changes

Water boils at 100 °C, goes into the gaseous state and turns into steam.

Water is liquid at normal pressure and temperature (1 atm and 25°C). It remains liquid between 0 °C and 100 °C. At temperatures below 0 ºC, water transforms into a solid (ice) and at temperatures above 100 ºC, water transforms into a gas (steam).

If water is mixed with other substances, the boiling and freezing points of the mixture will be different from those of unmixed water. This occurs because of interactions between the water molecules and the particles of the dissolved substance.

It may help you: States of matter

The water molecule

The water molecule is made up of one oxygen atom and two hydrogen atoms. It has non-linear geometry: the oxygen atom is located in the center and the two hydrogen atoms are forming an angle of 45º.

The geometry of this molecule gives it polarity, that is, the property of separating electrical charges in the molecular structure. For this reason, substances that dissolve in water are polar or have considerable polarity.

On the other hand, water molecules form hydrogen bonds, which are attractive electrostatic forces that are generated between an electronegative atom and a hydrogen atom linked by covalent bond to another electronegative atom. In the case of the water molecule, hydrogen bonds form between the oxygen atoms (electronegative) and the hydrogen atoms.

Chemical properties of water

Water is formed in the combustion reactions of organic compounds and in neutralization reactions between acids and bases.

Water reacts with metal oxides forming hydroxides and with non-metal oxides forming oxyacids.

Water reacts with highly electropositive chemical elements (elements of groups IA and IIA of the Periodic Table) to form hydroxides.

Organic and inorganic compounds can be hydrolyzed by reacting with water.

Water as a component of the body

Water is a major component of the body of living organisms. In humans, water makes up approximately 70% of their body. In living beings, it is essential for digestion, nutrient absorption and waste elimination.

Due to its ability to dissolve many chemical compounds, water plays a fundamental role in the various chemical reactions of metabolism. In addition, water serves as a means of transporting molecules across the cell membrane.

On the other hand, the excretion products of living organisms are dissolved in water for better processing.

Water cycle in nature

The water cycle in nature, also called the hydrological cycle, is the process of water circulation through the different parts of the hydrosphere. The hydrosphere is made up of the water found above and below the Earth’s surface.

During the water cycle in nature, water goes through different processes, and also transforms into different states of aggregation (liquid, solid and gas). Thus, the processes of the water cycle are:

Evaporation. It is the transformation of water that forms oceans, rivers, lakes and seas into water vapor. This process occurs when the temperature increases.
Perspiration. It is the formation of water vapor as a result of the transpiration of plants and the sweat of animals.
Sublimation. It is the transformation of solid water into gaseous water. This process occurs in glaciers, which are made of solid water.
Fusion. It is the transformation of solid water into liquid water. This process occurs when the temperature increases. It can be observed when snow melts and turns into water.
Solidification. It is the transformation of liquid water into solid water (ice). This process can be observed in clouds, where water transforms into ice when the temperature decreases, and then precipitates in the form of snow or hail.
Condensation. It is the transformation of gaseous water in the atmosphere into small droplets, which then form clouds.
Precipitation. It is the process by which, when the temperature decreases, the water droplets that form clouds combine with each other. This causes larger droplets to form that descend to the Earth’s surface in the form of precipitation.
Infiltration. It is the process by which water that falls on the earth’s surface due to precipitation becomes groundwater when it passes through the pores of the surface.
Runoff. It is the process by which water overflowing from a natural reservoir slides over the Earth’s surface. Water that moves by runoff is one of the main means of transporting sediments and nutrients that plants and some animals need to live.

Uses of water

Water must be used rationally to avoid contamination, waste and depletion. In this way, water can be used efficiently, which guarantees its quality.

Water uses can be classified as consumptive and non-consumptive:

Consumptive uses. These are those in which water is transported from a main body of water to the place where it will be used. Then this water (or at least part of it) does not return to the place from which it came.

Some consumptive uses of water are:

Domestic uses, such as cleaning homes, preparing food and personal hygiene.
Urban uses, such as cleaning shops, schools, hospitals and public institutions.
Industrial uses, such as in the production of refrigerants.
Agricultural uses, such as irrigating crops and producing fertilizers.

Non-consumptive uses. These are those in which water is used but not consumed. The water used returns to the environment from which it was extracted, although not necessarily to the same place.

Some non-consumptive uses of water are:

Recreational uses, such as in rivers, seas and lakes.
Uses for navigation, such as in the transportation of goods and people on ships.
Technological uses, such as in the construction of aquatic ecosystems.

Water contamination

The World Health Organization (WHO) defines contaminated water as “water whose composition has been modified so that it no longer meets the conditions for its intended use in its natural state.”

Water pollution causes the unusability and loss of natural water sources and reservoirs, which are used by living beings, both for consumption and to carry out other activities. There are various causes of water pollution, which can arise from different activities carried out by humans, as well as from natural sources of pollution.

Types of water pollution

Organic contamination (eutrophication). It is the contamination caused by excess nutrients and microorganisms. This type of contamination alters the natural composition of water, although it often does not persist over time and the changes in the natural composition are reversible.

Some factors that contribute to organic pollution are:

The increase in the amount of algae and decomposer organisms.
The presence of microorganisms originating from waste…