Chemistry is the study of what matter contains and how matter changes.
In this discussion the topic is how water, as a material substance, decomposes or changes into another material substance, a different form of matter. How does this occur?
If I were to talk about this just from life experience alone I would say well, the human body decomposes and the human body is something like 80 % water so yes, water does decompose.
A human body is said to turn to dust,... "earth to earth, ashes to ashes, dust to dust". So, does that mean the water in the body turns to dust, earth or ash?
Well, no actually. It can't because the water did not come from these, water is not composed of dust. Matter, in order to decompose, must be broken down into the pure elements it is created from.
Substances such as water are composed of pure elements, as in the periodic table of elements. The H2 and the O are those pure elements of matter on the table, hydrogen and oxygen. And those elements of Earth, Air, Fire and Water, these are not on the table. So why are these referred to as the four elements?
This brings in atoms and molecules.
Molecules are formed of the smaller atoms of different types that get combined and make up the substance of matter. These are compound substances because more than one type of atom is combined into a molecule.
Elements are also made of atoms, but a pure element is made of a single atom, single meaning only one type, not a combination of multiple types of atoms.
A pure element does not decompose because in the forms of matter, the material world, there are no smaller parts than the atom. In the science of chemistry an atom is the foundation block of matter. The study of subatomic particles, anything smaller than an atom, is the science of physics and focuses on the non material, the worlds beyond our senses.
Back to Water as a substance, and actually a compound substance.
Water is not an element on the periodic table of elements even though we refer to earth air fire and water as elements of nature. This is because it is combined from 2 types of atoms, a hydrogen atom 2 parts, and an oxygen atom 1 part. But water is still called an element, so technically it is a compound element. Gets confusing doesn't it.
This is a good place to pause and take a look at the point of reference which is helpful,
Hydrogen and oxygen are two pure elements that combine to form pure water. So it would seem that water can de-compose because it is composed of more than one atom. Lets find out. How does water actually decompose? To do this it has to break down into its simpler or simplist elements, or smallest atoms.
It is easy to think of steam as the way that water decomposes but actually this is not the case. Steam is water. We can cause the form of water to change to an airy or gaseous form as steam by heating it, and we can change its form to ice by freezing it. But if you cool steam it returns to liquid water form and if you heat ice it returns to liquid water. It is alway water.
To decompose is to become something that is no longer the substance water. This is to break it back down to the pure elements that caused it to form, which for water are hydrogen and oxygen.
The only way water will decompose is through ELECTRICITY. It is the electromagnetic force that can pull, or attract the atoms away from the combined form of elements that composes the substance of water.
As a side note, the way the two pure elements of H and O combine is through coming together and exploding. But that is a subject for a different day.
Electricity and Water. Here is where it gets confusing again so before going on, we know know that :
* in chemistry water is not an element but a compound substance that is composed of pure elements;
* pure elements can not be broken down, but these can combine to form substances;
Okay moving on to pure water.
Most of the water we live with and around is NOT pure water, or water in its pure state. These days most water such as tap water, rivers, lakes, or rainwater is not pure. These actually contain additional substances as minerals, and other contaminants in the form of chemicals, chlorine, etc., and rainwater can even contain salt.
Water dissolves many substances such as minerals and salts and when the dissolved substances are found in water then ions are present.
Ions are positive or negative charged atoms or molecules.
from the POINT OF REFERENCE
Pure water does not contain ions and so has no electric charge, no positive no negative atoms.
PURE Water is simply two parts pure hydrogen and one part pure oxygen, nothing else.
And pure water does not interact with, does not conduct, electricity. So this sounds to me like electricity can not change pure water. In order for water to decompose it must be made impure. Interesting.
NOW WE HAVE: Water... and pure water, Elements and pure elements, Ions, positive + or negative -
Ions are the atoms that have lost the balance of zero charge and carry a(+) or (-) charge. An atom becomes an ion when a disruption causes it to either lose or gain electrons.
The Periodic Table of Elements lists 118 elements and most of these are known as metals, such as gold, copper and others, and metals are conductors of electricity. Electricity moves through the metals. Electricity is the flow of electrical power or charge.
A conductor of electricity is matter, material substances, that electricity can flow through because a part of the atoms forming the substance has elements of metals, or dissolved metals. The nonmetal elements do not conduct electricity, so material substances that do not have an element of metals will not interact with or conduct electricity, such as glass, rubber, plastic, cotton...
We all likely learned that water and electricity don't mix because electricity can pass through water- impure water. I can remember as a kid playing in the pool at home or at our friends, and if a summer storm rolled in the parents would come out and get everyone out of the pools- LIGHTENING!! We all got out right away.
Electricity is what can cause water to decompose. It isn't a ZAP pOw bANG kind of deal, its a chemical process created to cause the change.
The process for decomposing water is called Electrolysis.
One more time, to decompose water it must be made impure.
The sources relied on for this exploration are a few old books, some volumes of science encyclopedia from the 1970's, a couple of modern books and a few bits from internet sites. The purpose of sourcing various old books for learning or explaining topics of science is because these are almost always far easier to understand than internet sites and modern source books. But the modern works are useful and will bring the topic relatively up to date.
POINTS OF REFERENCE ELECTRICITY GLOSSARY CHEMISTRY SCHOOLERS
