Introduction to chemistry

Chemistry is one of the ancient and main disciplines of sciences. Various kinds of changes such as formation, destruction's, growth, transformation, production etc. are discussed in chemistry. The practice of chemistry has been continuing for a number of millennial. The process of beautifying clothes by applying dyes was on track in the Indian sub continent about 5000 years ago. Men started making metallic weapons, columns and statues quite a long ago. In ancient times, precious metals like gold, silver, lead etc. were extracted from mines using chemical technologies. Gold was extracted by the Egyptians during 2600 B.C that is adored as a classy and precious metal till today. The practice of chemistry during the ancient and Middle Ages is known as Al-chemy. The word Al-chemy takes its origin from the Arabic word Al-chimia which would signify the Egyptian civilization. The Ancient Egyptian civilization became capable of meeting the needs of its people to a great extent through the practices of chemistry. Now a day, in mills and industries, the manufacturing of many consumer products starting from oil, sugar, paper, pen, medicine, cloth, shampoo, soap, rod-cement etc. is done through the use of chemistry. What is interesting is, present time chemistry is not confined only within the activities of industries and testing or research laboratories. If we observe the incidents happening around us, we will see the presence of chemistry everywhere. Some events are cited in table-1 for example.

Table-1: Presence of chemistry

Subject	Analysis
Mango becomes yellow as it ripens	Color is a chemical substance. The change in the color of mango to yellow means the creation of yellow colored new compound in the mango through biochemical process.
Rust in iron	Iron is hard, rust is fragile. Pure iron in presence of moisture reacts with oxygen of air and form a substance named iron oxide, which is generally known as rust.
Burning of wood, kerosene, natural gas or candle	These substances are mainly made of carbon compound. For example, wood is mostly cellulose, natural gas is methane and wax is a compound of carbon and hydrogen. Burning these substances means the burning of carbon compound, which is a kind of chemical reaction that results in the production of carbon dioxide gas, water vapor and heat.

So it can easily be assumed that, chemistry is somehow related to the different changes happening in our environment. The acts of making differences in the tastes of food through cooking may be called a kind of chemistry. In fact, from the ancient civilization to modern age, the immense journey of chemistry is observed in the society, that is, in almost all fields of science.

Concepts of Chemistry

Chemistry is one of the diverse branches of physical science. It is known as the science for life. The practice of chemistry has been in constant increase since the ancient time. The present day chemical industries have been evolved from the early practices of the Alchemists. Chemistry as a discipline encompasses a wide range of areas. It has always been devoted to the welfare of human and its environment. Therefore, in this age of information technology, it is necessary for all to know where and with which processes chemistry is involved in so that we can be benefited from applying the knowledge in our daily life.

Scope of chemistry

The scope of chemistry is enormous, which is devoted to serve to human race. The practice of chemistry is increasing with the pace of time. Let us consider the use of chemistry in our life. You have got up from bed with a heavy breathing and after brushing teeth, washed your hands and faces with water. Then, you have sat in front of your table to study after massaging an oily substance in your hands and mouth and combing your hair with a comb. Opening the red covered book you have seen the writings on white paper with black ink – chemistry is present in all these. After studying for some time, you wrote the answers to some questions in your exercise book with a pen or pencil. After that you had your food, and started for school wearing a white shirt and a blue pant. On your way to school, you saw a farmer using fertilizer in his garden or field. You also noticed a motor cycle running past you with emitting smokes. Chemistry is also present in all these incidents. Now consider the presence of chemistry in the usable things shown in Table-2. Table-2 Example of thinking about the scope of chemistry.

Substance	Element	Source
Air taken by inhalation	Mostly oxygen	Environment, air.
Brush, comb, artificial color, paper, exercise book, ink, pencil, pen	Made by the combination of different chemical compounds	Made in industries through the chemical changes of different materials
Drinking water	Pure water is made of hydrogen and oxygen atoms. There are other minerals too in drinking water.	Water exists in nature, e.g. river, drain, canal, bill, ocean, rain, water fall etc.
Food	Starch, protein, fat all are organic compounds and different mineral substances.	Plants (by photosynthesis) and animals produce and deposit foods by different process. When we take food, metabolic process occurs in our bodies and we get energy.
Shirt and pant	They are made from the combination of organic compounds and fibers.	Clothes are made in textiles and fabrics industries by combining dyes with natural or synthetic fibers made of different compounds through chemical reactions.
Fertilizer	These are made of oxygen, nitrogen, carbon, phosphorus etc. and combination of different chemical compounds.	Fertilizers are manufactured in industries by chemical reactions. Chemical fertilizers supply nutrients the soils with nutrients for the plants.
Motor cycle and its energy to move	It is made by the combination of different parts made of various metals and plastics. A motorcycle gains the energy to run by combustion of petroleum.	Metals are extracted from the minerals using chemical methods. Plastics are also made in industries by chemical reactions. Combustion of petroleum is a chemical process.

Relation of chemistry with the other brunches of Science

We have learned that chemistry is one of the main branches of science. There is a particular relation of chemistry with the other branches of science like mathematics, physics, zoology, environmental science, geological science etc. In fact, as the other branches of science are dependent on chemistry, similarly, the explanations and theoretical concepts of many events of chemistry are given with the help of other sciences.

You have read in life cycle that, directly or indirectly, plants serve as the source of foods for all animals. Plants deposit foods in different ways by a bio-chemical process called photosynthesis. Again animal body is made of different complex molecules such as protein, fat, compounds of calcium, DNA etc. the birth and growth of animal function through a bio-chemical process, which is a subject of biology.

In modern time, features well-known as the contribution of science like electricity, magnet, computer and theory of different electronic production and uses are discussed in physics. If we observe, we can see that all these materials are produced by the combination of different chemical properties of matters. The production and distribution of electricity may be considered here for example. Electricity is produced from the combustion of oil, gas, and coal, that is, from the heat generated through chemical reactions and distributed by the flow of electrons of metallic wire (e.g. copper). Various small parts of computer and other electronic goods like- CD, memory disk, monitor are produced by the combination of chemical properties of different matters. On the other hand, it is said that, the amount of copper that is already used in production of computer and other electronic goods is greater than the amount is still stored unused in nature. If copper is being used in this rate, one day it will be finished. Besides, the amount of such unusable goods will increase day by day and will cause harm to our environment. So it is necessary to recycle copper from those goods and to reuse. It can also be done by practicing chemistry.

On the other hand, plant and animal bodies get rotten after death and mix with soil through various microbial processes. Due to the absorbed heat and pressure of earth the materials which mix with soil undergo more chemical changes. As a result, they are converted to different minerals such as, petroleum; coal, natural gas etc. In atmospheric science identification of the ozone layer and ozone layer depleting gases are performed by different process of chemistry.

Now the dependency of chemistry on the other sciences can be considered. It is impossible to present the theories of chemistry or to acquire the theoretical knowledge of chemistry without mathematics. Calculations in chemistry, derivation of a rule and mathematical relations all are mathematics. Quantum mechanics is, in fact, mathematical calculations to explain the atomic structure. On the other hand, different experiments in chemistry are instrument dependent. The principles of these instruments or experimental principles are established on the basis of physics. From the above discussion it is understood that, there is a strong relation between chemistry and the different branches of science.

Importance of learning chemistry

We have understood from our reading of the scope of chemistry that, chemistry is always involved in providing basic human needs like- food, clothing, housing, medication and material of education. It is worth mentioning here that, the belief held by people of different sectors of the society that chemical substance means something hazardous, it is not correct.

Whatever we are eating, such as, rice, pulses, oil, sugar, salt and what we are using like soap, shampoo, detergent powder, medicine etc. are all chemical substances. Aren’t they?

The fertilizers and insecticides used in agriculture are all chemical substance. Insects are prevented from destroying the crops by using insecticides. We are using coil or aerosol to prevent mosquitoes. Soaps, shampoo, detergents are used in cleaning. We take medicines, antibiotics and vitamins to maintain our health. Various types of natural substances like turmeric, henna and artificial cosmetics and colors are used in beautification. In addition to that we are taking various types of herbal medicines and other materials to protect our health and for beautification. Sometimes inexperienced and dishonest people or farms produce and distribute these materials. Banned chemicals are being used unconsciously or dishonestly to prevent fish and meat from being rotten and to get fruit ripen quickly without considering the damage they cause to human health. Similarly illegal and non-food graded dyes are being using to make foods attractive.

To preserve processed foods for a long time preservatives are used specially in juice, sauce, cake, biscuit etc. Processed food without preservative may be harmful for life, but unfortunately, in most cases, in processing these foods excess amounts of forbidden and non food graded preservatives are uses.

On the other hand the heat used in burner for cooking is created by burning of wood or natural gas, where heat, carbon dioxide and other substance are produced from the reaction of oxygen in the air, wood or natural gas. It is worth mentioning that if wood and natural gas is burnt in presence of insufficient air, a gas called carbon-mono-oxide, which is very harmful for human health may be produced. Besides, on burning of wood or coal harmful carbon particles are produced, we call it soot (Kali), when they settle on the wall of the container. In the same way carbon dioxide gas is being produced from industries and automobile engines, which is very harmful to the environment.

Excess fertilizer, pesticide, soap, detergent, shampoo, etc. are polluting the soil and water of rivers and canals. We take the smoke of mosquito coil and aerosols with our inhalation. We use the artificial cosmetics, colors and herbals which reach to the different parts of our body with blood circulation. On the other hand, the produced carbon dioxide on production of heat or energy go to air and contribute to the increase of the temperature in our atmosphere.

We know, excess use of chemical fertilizer causes harm to the plants even may cause them to die. Similarly carbon-mono-oxide gas which is very harmful for human is produced on burning of wood or coal with limited supply of air. Excess doses of medicines may even cause people to die. Therefore, it is clear that for good results, the recommended uses of chemical substances are necessary and that can be ensured only by thorough understanding of chemistry. On the other hand, one can be aware of the risk factors and hazards of various chemical substances from studying chemistry which can build up us as conscious citizens. Along with this we, the users and manufacturers of various products can play important roles in protecting our society and environment by ensuring the proper uses of such products through quality assessment. Therefore, it is clear that, it is very important for everyone to have some knowledge of chemistry.

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