Chemistry - Interesting Things to know about it

Chemistry is the scientific study of the properties and behavior of matter. It is a natural science that covers the elements that make up matter to the compounds composed of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they undergo during a reaction with other substances. In the scope of its subject, chemistry occupies an intermediate position between physics and biology. It is sometimes called the central science because it provides a foundation for understanding both basic and applied scientific disciplines at a fundamental level.

Chemistry addresses topics such as how atoms and molecules interact via chemical bonds to form new chemical compounds. A chemical reaction is a transformation of some substances into one or more different substances. The basis of such a chemical transformation is the rearrangement of electrons in the chemical bonds between atoms. It can be symbolically depicted through a chemical equation, which usually involves atoms as subjects.

In chemistry, the matter is defined as anything that has rest mass and volume (it takes up space) and is made up of particles. The particles that makeup matter have rest mass as well – not all particles have rest mass, such as the photon. Matter can be a pure chemical substance or a mixture of substances.

The atom is the basic unit of chemistry. It consists of a dense core called the atomic nucleus surrounded by a space occupied by an electron cloud. The nucleus is made up of positively charged protons and uncharged neutrons (together called nucleons), while the electron cloud consists of negatively charged electrons that orbit the nucleus. In a neutral atom, the negatively charged electrons balance out the positive charge of the protons. The nucleus is dense; the mass of a nucleon is approximately 1,836 times that of an electron, yet the radius of an atom is about 10,000 times that of its nucleus.

A chemical element is a pure substance that is composed of a single type of atom, characterized by its particular number of protons in the nuclei of its atoms, known as the atomic number, and represented by the symbol Z. The mass number is the sum of the number of protons and neutrons in a nucleus. A compound is a pure chemical substance composed of more than one element. The properties of a compound bear little similarity to those of its elements. The standard nomenclature of compounds is set by the International Union of Pure and Applied Chemistry (IUPAC). Organic compounds are named according to the organic nomenclature system. The names for inorganic compounds are created according to the inorganic nomenclature system. A molecule is the smallest indivisible portion of a pure chemical substance that has its unique set of chemical properties, that is, it's potential to undergo a certain set of chemical reactions with other substances.

Here are some interesting facts about Chemistry:

• Ozone, the triple oxygen molecule that acts as a protective stratospheric blanket against ultraviolet rays, is created in nature by lightning. When it strikes, the lightning cracks oxygen molecules in the atmosphere into radicals which reform into ozone. The smell of ozone is very sharp, often described as similar to that of chlorine. This is why you get that “clean” smell sensation after a thunderstorm.
• Typically, when something is cold, it shrinks. That’s because temperature describes atomic vibration — the more vibration, the more space it takes, hence expansion. Water is an exception. Even though it vibrates less when it’s frozen, the ice occupies more volume. That’s due to the strange shape of the water molecule.
• At ground zero, during the Universe’s singularity, the very first chemical element was hydrogen. All the others followed by fusing hydrogen into helium, which then fused into carbon and so on. Approximately 73% of the mass of the visible universe is in the form of hydrogen. Helium makes up about 25% of the mass, and everything else represents only 2%. By mass, hydrogen and helium combined make up less than 1% of the Earth.
• When you step inside a bathtub, the water level will immediately go up, per Achimedes’ law. But when you add a volume of sodium chloride (salt) to a volume of water, the overall volume actually decreases by up to 2%. What gives? The net reduction in observed volume is due to solvent molecules that become more ordered in the vicinity of dissolved ions.
• Though made of the same stuff, the difference between a crown jewel and pencil lead is given by form. Namely, diamond and graphite are arranged differently in space making them allotropes of carbon.
• When a collision takes place, the car’s sensors trigger an electrical impulse which in a fraction of a second dramatically raises the temperature of the salts. These then decompose into harmless nitrogen gas, rapidly expanding the airbag.
• Famed chemist Glenn Seaborg was the only person who could write his address in chemical elements. He would write Sg, Lr, Bk, Cf, Am. That’s  Seaborgium (Sg), named after Seaborg himself; Lawrencium (Lr), named after the Lawrence Berkeley National Laboratory;  Berkelium (Bk), named after the city of Berkeley, the home of UC Berkeley;  Californium (Cf), named after the state of California; Americium (Am), named after America.
• Commonly, matter appears in one of the four states: solid, liquid, gas and plasma. The air we all breathe is gaseous but like any kind of matter, it can change its state when subjected to a certain temperature and pressure. Air is a mixture of nitrogen, oxygen, and other gases. The gas can be liquefied by compression and cooling to extremely low temperatures — under normal atmospheric pressure, air has to be cooled to -200°C and under high pressure (typically 200 atmospheres) to -141°C to convert into liquid. Liquid air is used commercially for freezing other substances and especially as an intermediate step in the production of nitrogen, oxygen, and argon, and other inert gases.
• While Earth is sometimes referred to as the ‘blue marble’ because it’s mostly covered in oceans and has a thick atmosphere, giving it a blue appearance, Mars is covered in a lot of iron oxide — these are the same compounds that give blood and rust their distinct color. In light of this, it’s no coincidence that Mars, which occasionally appears as a bright red ‘star’, was named after the Greek god of war.