Chemistry as a Subject

Chemistry as a Subject and as a Central Science

CHEMISTRY AS A DISCIPLINE

Human mind has always been very curious to make investigations and know about various activities/phenomena occurring around him. This curiosity has led him to collect information through experiments and observations. The curious mind has also been responsible for the research activities of various people all over the world.

The knowledge and data base acquired like this is then systematized in a way that the mankind takes maximum benefit out of it. This knowledge base is known as science. Science may, thus, be broadly defined as systematized knowledge gained by mankind through observations and experimentation. Science has been further classified into different branches due to its enormous expansion and diversified fields. Some examples are: Chemistry, Physics, Biology, Geology, etc. Chemistry is one of the most important discipline of science to which this present book is devoted.

CHEMISTRY AS A SUBJECT AND AS A CENTRAL SCIENCE

Chemistry may be defined as the branch of science which deals with the study of matter, its composition, its properties and the changes which it undergoes in composition as well as in energy during various processes.

The word chemistry has been derived from the word alchemy, which means ‘study of met also Alchemy itself might have come from al chemical marked effect on our present day life. Chemistry has helped us to meet all our requirement for better living. The continuous

research in the field of chemistry has resulted in the production of useful materials such as, clothes, drugs, artificial foods, plastics, rubbers, fertilizers, insecticides, weed killers, life

supporting products, etc., which have revolutionised our life.

Our life would have been very dull and dreary without the knowledge of chemistry. In fact, we can say, chemistry is everywhere in the world around us; it is, in what we eat; in what we breathe; in how we live and even in what we are.

CHEMISTRY – A CENTRAL SCIENCE

Modem chemistry is an abstract subject whose study presents a great intellectual challenges and rewards. It is a practical field at the hub of man’s future.

Modern chemistry is CENTRAL DISCIPLINE, which correlates almost all branches of science. It is used to study biological, physical, medical as well as environmental phenomena. For example, a chemist works with:

biologist to understand life processes and metabolic activities,
physicist to understand properties of matter and to develope new sources of energy,
geologist to probe outer and inner space,
physician to design new drugs and medicines,
ecologist to make improvement in environment,
engineers and technical manager to provide material and energy for better life.

Chemistry, thus responds to all social needs. It plays critical role in any attempt to: discover new processes; tap new energy sources; develop new materials feed the people properly; improve health and conquer disease, monitor and protect our environment.

BRANCHES OF CHEMISTRY

Chemistry can be broadly divided into Pure Chemistry and Applied Chemistry.

PURE CHEMISTRY

Pure chemistry deals with the attempt to get better understanding of nature.

Pure chemistry is further divided into three main branches. Organic chemistry, Inorganic Chemistry and Physical chemistry. These main branches have been further divided into large number of sub-sections. The main branches meaning divided into large number of sub-sections. The main branches are described briefly as follows:

Organic Chemistry. This branch of chemistry deals with the study of structure, chemical composition and characteristics of compounds of carbon and hydrogen elements (Hydrocarbons) and their derivatives.
Inorganic Chemistry. This branch concerns itself to the study of structure, composition and behaviour of the inorganic compounds, i.e., the compounds other than hydrocarbons or their derivatives. Such compounds are found in the crust of the earth and constitute non-living matter.
Physical Chemistry. This branch deals with the study of fundamental principles governing various chemical transformations and chemical systems. It is primarily concerned with laws and theories of different branches of chemistry.

APPLIED CHEMISTRY

Applied chemistry deals with the application of the knowledge of chemistry for the benefit of mankind. The different branches of applied chemistry are as under:

Analytical Chemistry. This branch involves collection of techniques which allows exact determination of the composition of the given sample of material. It has been further divided into two categories:

(a) Qualitative analysis. It deals with the identification of various constituent particles (atoms, ions, molecules) present in the material.

(b) Quantitative analysis. It deals with the estimation of various constituents in the material.

Industrial Chemistry. This branch deals with the chemistry involved in different industrial processes such as manufacture of various chemical substances.
Biochemistry. This branch concerns itself to the study of metabolic pathways and enzymology pertaining to living organism. It deals with molecular, cellular and chemical activities of living organisms.
Geochemistry. This branch deals with the chemical processes occurring on earth such as metamorphism of rocks, formation of petroleum, etc. It also deals with the composition of soils and rocks.
Petrochemistry. It is the branch of chemistry which deals with the transformation of crude oil (petroleum) and natural gas into useful products and raw materials.
Radiochemistry. It is a branch of chemistry which deals with the study of radioactive materials, both natural as well as man-made. It also involves the use of radioactive materials to study the pathways/mechanism of ordinary chemical reactions.
Biotechnology. It refers to the technological applications which uses biological systems, living organisms or their cterivatives to make or modify products or process for specific use. Biotechnology, infact, combines various disciplines like genetics, molecular biology, biochemistry, embryology and cell biology for developing techniques for beneficial effects.
Medicinal or Pharmaceutical Chemistry. It is scientific discipline at the intersection of chemistry and pharmacology, which is involved with designing synthesizing and developing pharmaceutical drugs. Medicinal chemistry involves the identification, synthesis and development of new chemical entities suitable for therapeutic use. Medicinal chemistry is highly interdisciplinary science that combines organic chemistry with biochemistry, pharmacology, *pharmacognosy; molecular biology, statistics and physical chemistry.

Environmental Chemistry. It is a branch of chemistry which deals with scientific study of chemical and biochemical phenomena that occur in natural places. Environmental chemistry is also an interdisciplinary science that includes atmospheric, aquatic, and soil chemistry along with analytical chemistry, environmental studies and other areas of science.

CAREER OPPORTUNITIES

Since chemistry is a central science because of its multidisciplinary nature, therefore, chemistry students can persue their careers in the field of industries, education, research work, government agencies and other non raditional fields. Some of the careers opportunities, that a student with degree in chemistry can have are as follows:

Industries. Chemical industries employ about 66% of all the chemists. The majority of them find opportunity in research and product development (Rand D), sales, or marketing. Many of them work in quality control analysis and testing products. Other find work in areas like industrial hygiene and safety or regulatory work for environmental compliance.

*pharmacognosy is a study of medicines derived from natural

Academic Institutions. Educational institutions employ about 26% of the chemists. Ph. D. degrees are required for most of academic positions at the colleges and universities. Some of chemists having graduation degree in education take up teaching assignments in high schools.
Government Agencies. Government-employ about 7Cfr: of all the chemists. Federal, local and state Government agencies hire chemists for variety of jobs including basic research, testing work required to enforce government regulations, technical program managers, authors/ editors of technical documents and government regulations.
Non-traditional Fields. A small percentage of chemists (about 1%) find work in non -traditional fields. They get opportunities to become patent lawyers, science writers, information specialists, technical librarians, technical consultants or business owners.

Group Discussion

Identify two applied chemistry professions and explain the chemistry they practice.

Hints: For reference, the two important professions associated with applied chemistry are being discussed as follows:

Analyst: Analysts find jobs in chemical industry, food industry and pathological laboratories. In chemical industries, they control the quality of final product through chemical analysis of the product. In food laboratories, they analyse the food items to detect adultration. In pathological labs they carry out chemical tests on sample of blood or urine to help the doctor for diagnosis of disease.
Research scientist. Research scientists find jobs in pharmaceutical companies where they can use their knowledge of chemistry in developing more convenient and economical methods for the synthesis of drugs. They can also help in designing new drugs.

Various careers associated with chemistry.

Chemistry is the study of matter, its composition, its properties and changes which it undergoes in composition as well as energy during various transformations. Chemistry is a central science discipline which correlates various important branches of science. Chemistry can be divided into pure and applied chemistry. Pure Chemistry has three main branches viz organic, inorganic and physical chemistry while chemistry applied has branches namely biochemistry, analytical

chemistry, radiochemistry, geochemistry, petro chemistry, environmental chemistry and biotechnology.

EVALUATION

Which branch of pure chemistry deals with the study of compounds associated with non-living sources?

(a) Physical chemistry (b) Organic chemistry

Which of the following is not a applied chemistry?

(a) Geochemistry (b) Biochemistry

In order to design new drug, a chemist has to seek the help of

(a) Engineer (b) Geologist

The branch of chemistry which deals with the study of hydrocarbons is called

(a) Organic chemistry (c) Radiochemistry

(b) Inorganic chemistry (d) Nuclear chemistry.

Fill in the Blanks
Complete the following sentences by supplying appropriate words:

(i) Ecologist and chemist work together to ….. .

(ii) The branch of pure chemistry which deals with study of fundamental laws and principles is called …..

(iii) Qualitative analysis deals with ….. .

(iv) Radiochemistry deals with the study of ….. substances.

(v) The phenomenon of metamorphosis of rocks is studied by ….. branch of chemistry. m.

Discussion Questions

Define chemistry and its various disciplines.
Comment on the statement that chemistry is a central science discipline.
Write the names of various disciplines of applied chemistry. Define any two of them.
Name and define various branches of pure chemistry.
Give a brief account of various career options of degree holder in chemistry.

THE SCIENTIFIC METHOD

When conducting research, scientists use the scientific method to collect measurable, empiricalevidence in an experiment related to a hypothesis (often in the form of an if/then statement), the results aiming to support or contradict a theory.

The steps of the scientific method s are:

Make an observation or observations.
Ask questions about the observations and gather information.
Form a hypothesis — a tentative description of what’s been observed, and make predictions based on that hypothesis.
Test the hypothesis and predictions in an experiment that can be reproduced.
Analyze the data and draw conclusions; accept or reject the hypothesis or modify the hypothesis if necessary.
Reproduce the experiment until there are no discrepancies between observations and theory.

CHEMISTRY LABORATORY COMMON EQUIPMENT

Balance (electronic)	Beakers	Bunsen Burner	Buret
Clay Triangle	Crucible	Crucible in Triangle	Crucible Tongs
Dropper Pipets	Dropper in action	Erlenmeyer Flasks	Evaporating Dish
Forceps	Funnels	Goggles	Graduated Cylinders
Pinch Clamp	Pipets and Bulbs	Plastic and Rubber Policemen	Ring Clamp & Stand
Scoopula	Stirring Rods	Thermometers	Test Tubes in Rack
Test Tube Holder	Tube & Holder in Action	Utility Clamp	Clamp in action
Wash Bottle	Watch Glasses	Wire Gauze	Combined for Heating

A List of Chemistry Laboratory Apparatus and Their Uses

Functions of common pieces of laboratory equipment.

In most labs, you’ll encounter the same basic apparatus. Here, the use for each is explained. You will learn about:

Safety goggles and safety equipment
Beakers
Erlenmeyer flasks, AKA conical flasks
Florence flasks, AKA boiling flasks
Test tubes
Watch glasses
Crucibles
Funnels
Graduated cylinders
Volumetric flasks
Droppers
Pipettes
Burets
Ring stands, rings, and clamps
Tongs and forceps
Spatulas and scoopulas
Thermometers
Bunsen Burners
Balances

Safety Goggles and Safety Equipment

Safety goggles.

The first and foremost rule of any laboratory is to be safe! This may seem obvious, but people often disregard safety protocols for one reason or another, putting themselves and those around them in danger. The best thing you can do is to make sure you follow all safety protocols at all times.

Safety goggles are required wear in all chemistry labs. Not wearing them puts you in danger of eye irritation and possibly blindness in the case of an accident. A small droplet of acid could splash out of the container at any time. Better safe than permanently blinded!

Latex gloves should be used when there is a possibility of corrosive chemicals spilling onto your hands.

A lab apron or coat can also prevent injury in case of spills or splashes.

Never wear open-toed shoes or sandals in a lab.

Beakers

Beakers of various sizes.

A beaker is a common container in most labs. It is used for mixing, stirring, and heating chemicals. Most beakers have spouts on their rims to aid in pouring. They also commonly have lips around their rims and markings to measure the volume they contain, although they are not a precise way to measure liquids. Beakers come in a wide range of sizes.

Because of the lip that runs around the rim, a lid for a beaker does not exist. However, a watch glass can be used to cover the opening to prevent contamination or spl

Erlenmeyer Flasks, AKA Conical Flasks

Erlenmeyer flask.

Also known as a conical flask, the Erlenmeyer flask was named after its inventor in 1861. It has a narrow neck and expands toward its base. This allows easy mixing and swirling of the flask without too much risk of spilling. The narrow opening also allows for the use of a rubber or glass stopper. It can easily be clamped to a ring stand as well as heated or shaken mechanically.

Once again the marks on the side are meant primarily for estimation rather than precision.

An important safety tip here is to never heat this flask while it is capped. This could cause a pressure build-up that could result in explosion.

Florence Flasks, AKA Boiling Flasks

Also known as a boiling flask, the Florence flask has a round bottom and a long neck. It is used to hold liquids and can be easily swirled and heated. It can also easily be capped by rubber or glass stoppers.

Once again, safety dictates that this flask never be heated when capped. Pressure build-up and explosions can and do occur.

Test Tubes

Test tubes held in spring clamps.

A test tube is a glass tube with one end open and the other end closed. The closed end is rounded. Test tubes are used to hold small samples. They are primarily used for qualitative assessment and comparison. A common place to see these is the biochemistry lab. When a large number of samples need to be tested and compared, test tubes are used to make this easier. They are also easily capped with a rubber or glass stopper.

They are generally held in a test tube rack specifically designed for the purpose. If heated or unsafe to touch with bare hands, test-tube tongs can be used to move them.

Never heat a capped test tube.

Watch Glasses

A watch glass holding a powder.

A watch glass is just a round piece of glass that is slightly concave/convex (think of a lens). It can hold a small amount of liquid or solid. They can be used for evaporation purposes and also can function as a lid for a beaker.

CRUCIBLES:

Crucibles

A crucible is a small clay cup made of a material that can be heated to extreme temperatures. This is because they are used for heating. They come with lids.

Funnels

An inverted funnel positioned above a watch glass.

A lab funnel is just like any other funnel except that it was designed to be used in a laboratory setting. They can be made of plastic or glass and can have either a short stem or a long stem, depending on what they are needed for. There are several sizes that can be chosen from based on the amount of liquid that needs to go through them quickly.

Graduated Cylinders

Graduated cylinders.

This is a primary measuring tool for the volume of a liquid. There are several markings up and down the length of the container with specific increments. Graduated cylinders come in many sizes. The smaller they are, the more specific the volume measurements will be.

When reading the volume from a graduated cylinder, you will notice that the liquid seems to have an indentation. The liquid around the edges will be higher than the liquid in the center, sloping down loke the sides of a trampoline when someone is standing in the middle. This is called the meniscus. Line the lowest point of the meniscus up with the nearest marking, keeping the cylinder level. That is how to properly read the volume.

Volumetric Flasks

A 500-ml volumetric flask.

A volumetric flask is a round flask with a long neck and flat bottom. It is used to measure an exact volume of liquid. There is a small line on the neck that indicates how far to fill the bottle (Use the bottom of the meniscus). They come with special caps that will not let anything in or out.

Remember that temperature affects volume; therefore avoid using liquids that will fluctuate in temperature (hot water that will cool, for example).

Droppers

A glass dropper.

These are small glass tubes with narrow tips and a rubber bulb on the end. They suck up liquid that can then be squeezed out in small drops. These can be used to add an indicator to a solution about to be titrated.

Pipettes

A Pasteur pipette.

There are a large variety of pipettes designed to accomplish specific goals. However, they are all for measuring an exact volume of liquid and placing it into another container.

Buirets

A Mohr burette.

A buret is a glass tube that is open at the top and comes to a narrow pointed opening at the bottom. Right above the bottom opening is a stopcock that can be turned to control the amount of liquid being released. There are markings along the length of the tube that indicate the volume of liquid present.

A buret is used for extremely accurate addition of liquid. By adjusting the stopcock, the amount of liquid that is released can be slowed to a drop every few seconds. Burets are one of the most accurate tools in the lab.

Burets are set up by using a buret clamp in combination with a ring stand, discussed below.

To determine how much liquid is added, write down how much is initially in the buret. Then when you’re finished adding, write down how much is left. Subtract the final amount from the initial amount and you have the volume of liquid added.

Remember to measure from the bottom of the meniscus!

Ring Stands, Rings, and Clamps

The ring stand is used to suspend burets, beakers, flasks, crucibles, etc. above other containers or in some cases a heat source (Bunsen burner, discussed below).

Always make sure everything is clamped to the stand tightly. When clamping glass, be careful not to shatter the glass. Only tighten that end until snug.

When using a ring on the stand, there are usually other pieces necessary to accomplish the goal. Wire mesh is laid across the ring to distribute evenly heat and support the beaker. A clay triangle with an open center is used to suspend crucibles.

Make sure everything is balanced! Do not let the whole setup tip over.

Tongs and Forceps

Foreceps.

Tongs and forceps are for grabbing things that should not be touched by hand. Some tongs are specially made to hold beakers, others to hold test tubes, and so on. There are also general tongs.

Forceps are used to grab small things like solid chemicals that are broken into chunks, so they can be safely handled and added to containers.

Spatulas and Scoopulas

Two scoopulas.

Spatulas and scoopulas are for scooping solid chemicals. The typical use for these in a lab is scooping chemical out of its original container onto a weigh boat so that it can be weighed on a balance.

Thermometers

Glass thermometer

A laboratory thermometer is a glass thermometer used for measuring the temperature of liquids.

Bunsen Burners

A lit Bunsen burner.

A Bunsen burner is a mechanical apparatus that is connected to a flammable gas source. There is a knob to adjust the amount of gas flow and a rotating collar that controls airflow. These both must be adjusted to get an ideal flame for heating purposes. The burner is lit with a striker.

Utmost safety is required when using a Bunsen burner.

Balances

Triple beam balance.

A balance is used to weigh chemicals. The chemicals are always in some form of container and never placed directly on the balance. It is important not to move a balance because they have been calibrated for the exact position they are in. Some balances have plastic housing with small doors to keep air currents from affecting the measurement. Close these doors whenever the balance is in use.

To use a balance to determine the weight of a chemical, first put the empty container that the chemical will be in on the balance. Once you have a reading, press the “tare” or “zero” button on the balance. Remove the container from the balance and add the chemical (never add chemicals to a container while it is on the balance). Reweigh after adding the chemical to find the weight of only the chemical.

It is important to keep the balance clean.