Applied Chemistry Online Test 9th Science Lesson 16 Questions in English

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Chemical principles and theories are applied to various fields in order to achieve specific results
or to solve real-world problems. This is called applied chemistry.

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The size and shape of materials influence their characteristics. Scientists found that materials having size about 1/1,000,000,000 metres show special characteristics.

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The Scientist started producing kind of special materials and studied the effect of size on properties. Thus a new branch of chemistry called ‘Nano chemistry’ was developed.

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Nano chemistry is a branch of Nano science that deals with the chemical applications of nanomaterial’s in nanotechnology. It involves synthesis and manipulation of materials at atomic and molecular level and the study of their physical and chemical properties.

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The word Nano has been derived from the Greek word ‘Nanos’ which is designated to represent billionth fraction of a unit.

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One nanometer (nm) is 10−9 or 0.000,000,001 meter.

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The DNA double helix is 2 nm across.

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The diameter of one hydrogen atom is around 0.2 nm.

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The properties of materials with nano meter dimensions are significantly different from those of atoms and bulk materials. This is mainly because the nano meter size of the materials render them, larger surface area, high surface energy, spatial confinement and reduced imperfections which do not exist in the corresponding bulk materials.

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The surface characteristics of nanoparticles are the main criteria to be considered for applications.

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Highly sophisticated instruments like Scanning Electron Microscope (SEM), Tunneling Electron Microscope (TEM) and Atomic Force Microscope (AFM) are used to analyze the surface properties of a nanoparticle with high resolution.

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The metallic nanoparticles can be used as very active catalysts to analyze the surface properties of a nanoparticle with high resolution.

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Nano coatings and nano composites are found useful in making variety of products such as sports equipment, bicycles and automobiles etc.

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Nanotechnology is applied in the production of synthetic skin and implant surgery. Nano materials that conduct electricity are being used in electronics as minute conductors to produce circuits for microchips. Nano materials have extensive applications in the preparation of cosmetics, deodorants and sun screen lotion.

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Nanoparticle substances are incorporated in fabrics to prevent the growth of bacteria.

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Nanoparticles are unstable when they react with oxygen. Their exothermic combustion with oxygen can easily cause explosion. Because nanoparticles are highly reactive, they inherently interact with impurities as well.

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Nano materials are biologically harmful and toxic. It is difficult to synthesis, isolate and apply them. There are no hard-and-fast safe disposal policies for nano materials.

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Pharmaceutical chemistry is the chemistry of drugs which utilizes the general laws of chemistry to study drugs.

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Pharmaceutical chemistry deals with preparation of drugs and the study of chemical composition, nature, behavior, structure and influence of the drug in an organism, condition of their storage and the therapeutic uses of the drugs.

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Drug discovery is the core of pharmaceutical chemistry.

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The chemicals used for treating diseases are termed as drug. The word drug is derived from the French word ‘droque’ which means a dry herb.

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According to World Health Organization a drug is defined as follows: ‘It is a substance or product that is used or intended to be used to modify or explore physiological systems or pathological states for the benefits of the recipient’.

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A drug must possess the following characteristics: It should not be toxic. It should not cause any side effects. It should not affect the receptor tissues. It should not affect the normal physiological activities. It should be effective in its action. 

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The main sources of drugs are animals and plants. The modern manufacturers adopt many chemical strategies to synthesize drugs for specialized treatments which are more uniform than natural materials.

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Drugs fall into two general categories:

• The drugs that are used in the treatment and cure of any specific disease.
• The drugs that have some characteristic effect on the animal organism but do not have any remedial effect for a particular disease. This class includes, morphine, cocaine etc.

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The drugs that have some characteristic effect on the animal organism do not have any remedial effect for a particular disease. This class includes, morphine, cocaine etc.

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The drugs which cause loss of sensation are called Anesthetics. They are given to patients when they undergo surgery.

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General anesthetics: They are the agents, which bring about loss of all modalities of sensation, particularly pain along with ‘reversible’ loss of consciousness.

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Local anesthetics: They prevent the pain sensation in localized areas without affecting the degree of consciousness. For example, dentist give patients this kind of anesthetics when carry out a minor surgery in teeth.

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Chemicals as Anesthetics: There are three major chemicals which are used as anesthetics.

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Nitrous Oxide (N2O): It is a colorless, nonirritating, inorganic gas. It is the safest of the anesthetic agents. This is used after mixing general anesthetics like ether.

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Chloroform (CHCl3): It is a volatile liquid. It has pleasant smell and sweet taste. With oxygen it forms a toxic carbonyl chloride. Hence it is not used now.

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Ether: Diethyl ether or simple ether (C2H5-O-C2H5) is a volatile liquid. 

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Ether is mixed with a stabilizer 0.002% propyl halide. After absorption by tissues it attacks the central nervous system and makes the patient unconscious.

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Analgesics are the compounds which relieve all sorts of pains without the loss of consciousness. These are also called as pain killer or pain relievers. 

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Analgesics are effective in healing headaches, myalgia and arthralgia.

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Aspirin and Novalgin are the commonly used analgesics. Aspirin acts both as antipyretic as well as analgesic. Certain narcotics (which produce sleep and unconsciousness) are also used as analgesics.

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The analgesics are given either orally or applied externally. In general externally applicable pain killers come as ‘gels’.

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Antipyretics are the compounds which are used for the purpose of reducing fever (lowering the body temperature to the normal). They are taken orally as tablets and capsules.

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The most common antipyretics are aspirin, antipyrine, phenacetin and paracetamol.

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Antiseptic is a substance that prevents infections caused by disease causing microorganisms or pathogens.

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Antiseptics either kill the micro-organism or prevent their growth. Antiseptics are used externally to cleanse wounds and internally to treat infections of the intestine and bladder.

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Iodoform (CHI3) is used as an antiseptic and its 1% solution is a disinfectant. 0.2 % solution of phenol acts as an antiseptic and its 1% solution is a disinfectant. Hydrogen peroxide is a minor antiseptic mainly used for cleansing wounds.

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Malaria is a vector borne disease which causes shivering and fever. It raises the body temperature to 103-106 °F. It causes physical weakness with the side-effects in liver and also causes anemia.

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Extracts of roots and stems of certain plants are extensively used as antimalarial. Quinine is a natural antimalarial obtained from Cinchona bark.

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The last antimalarial discovered in 1961 is pyrimethamine. However, quinine, primaquine and chloroquine are some of the best antimalarial.

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Chloroquine is used specially to control malarial parasites such as plasmodium ovale, plasmodium vivax etc. It is not used in curing the disease. It is used as an additive with other antimalarial drugs.

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Many microorganisms (bacteria, fungi and molds) produce certain chemicals which inhibit the growth or metabolism of some other disease causing micro-organisms. Such chemical compounds are known as antibiotics.

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Antibiotics are chemicals inhibit the growth or metabolism of some other disease causing micro-organisms these need to be present only in low concentration to be effective in their antibiotic action.

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The first antibiotic ‘penicillin’ was discovered by Alexander Fleming in 1929 from the mold Penicillium notatum.

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Penicillin is extensively used for rheumatic fever, narrowing of heart wall, bronchitis, and pneumonia etc.

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There are three main sources of antibiotics: (i) Bacteria (ii) Fungi and (iii) Actinomycetes

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The original antibiotics like a lot of today’s antibiotics are derived from natural sources. Certain plant extracts, essential oils, and even foods have antibiotic properties. Example: Honey, garlic, ginger, clove, neem and turmeric.

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Quite often after eating oily and spicy food one may feel uncomfortable due to some burning sensation in stomach / food pipe. This is due to imbalance in the acidity in the stomach. Certain drug formulations provide relief from such burning sensation. These are known as antacids.

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Antacids are available in tablet as well as gel / syrup forms. These antacids contain magnesium and Aluminium hydroxides in addition to flavoring agents and color.

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The chemical reactions (chemical energy) that take place in the battery produce electricity (electrical energy). So when scientists realized that chemical energy can be converted into electrical energy and vice versa another branch of applied chemistry was developed. It is Electrochemistry.

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Electrochemistry is a branch of chemistry which deals with the relation between electrical energy and chemical change. It is mainly concerned with the processes taking place between the electrode and solution having ions called electrolyte.

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Only redox reactions that take place in a specific device can produce electricity.

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The device that makes use of a chemical change to produce electricity or electricity to produce chemical change is called Electrochemical Cell.

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An electrochemical cell may comprise of two major components.

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Electrode: It is a solid electrical conductor made of metal (sometimes non-metal like graphite). A cell consists of two electrodes. One is called Anode and the other is called Cathode.

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Electrolyte: It is made up of solutions of ions or molten salts which can conduct electricity.

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An electrochemical cell involves two reactions simultaneously.

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Oxidation: As we know already an oxidation is loss of electron. In electrochemical cells oxidation takes place at anode. Metal → Metal ion + electron (e-)

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Reduction: It involves gain of electron. Reduction takes place at cathode. Metal ion + electron (e-) → Metal

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Both the reactions take place simultaneously, the inter conversion of electrical and chemical energy in electrochemical cells involves a redox reaction.

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Based on the nature of the energy conversion, electrochemical cells are broadly classified.

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Galvanic Cell: It is an electrochemical cell which converts chemical energy into electrical energy i.e. it produces electricity from chemical reactions. It consists of two half cells namely anodic half-cell and cathodic half-cell.

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In anodic half-cell of galvanic cell the anode is in contact with its electrolyte whereas in cathodic half-cell, the cathode is in contact with its electrolyte. The anode and cathode are connected by a conductor wire.

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The electrolytes of half-cells are connected through a tube containing a saturated salt solution. It is called salt bridge. Thus in galvanic cell, both the half-cells are kept separately but stay connected electrically.

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At anode, oxidation takes place which releases electrons. These electrons are attracted by cathode and hence the electrons flowing from anode to cathode are gained in reduction reaction. As long as the redox reaction proceeds, there is a flow of electrons and hence electricity.

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Electrolytic Cell:  It is an electrochemical cell which converts electrical energy into chemical energy i.e. in electrolytic cells; electricity is used to bring about chemical reactions.  Here, both anode and cathode are in contact with same electrolyte and thus the half-cells are not separated. As seen in galvanic cells, electrolytic cell also involves redox reaction.

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Electrochemistry: It has been used to discover important technical processes for the production and purification of non-ferrous metals, and for the electro- synthesis of organic compounds. Electrochemistry is used to predict whether a particular reaction will occur or not.

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The detection of alcohol in drunken drivers is possible through the electrochemical redox reaction of ethanol.

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Production of metals like aluminum and titanium from their ores involve electrochemical reactions.

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Lead acid batteries, lithium-ion batteries and fuel cells are based on electrochemical cells. Fuel cell is used to bring about direct conversion of chemical energy into electrical energy.

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Isotopes are atoms with same number of protons and electrons and a different number of neutrons. Some isotopes are stable and stay forever. These are the elements that we see around us and find in nature.

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Some isotopes are unstable and they undergo disintegration by losing their energy in the form of radiation.

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Every element tries to attain stability by sharing, losing or gaining electrons (octet rule). Thus the unstable isotopes of elements lose their energy in the form of radiation to become stable.

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The Isotope which undergoes radioactive decay is called radioactive isotope or radioisotope. This property of isotopes is known as radioactivity.

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Uranium in the ground can decay into radon gas which can be very dangerous to humans. It is thought to be the second leading isotope to cause lung cancer.

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Radiochemistry is the study of chemistry of radioactive and non-radioactive isotopes. It includes both natural and artificial isotopes.

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Radiochemistry mainly deals with application of radioisotopes to study the nature of chemical reactions of non-radioactive isotopes of elements and applications of radioisotopes to various fields.

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Radioisotopes can easily be detected and estimated quantitatively. So they are used in radiochemistry for various applications. Radiochemistry mainly deals with study of chemical reactions of non-radioactive isotopes using radioisotopes. In addition to that it could find applications in medical field and environmental management also.

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Radiocarbon dating: It is a method by which the age of fossil wood or animal is determined using C-14 isotope.

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Radiotherapy: Radioactive isotopes are used in the treatment of many diseases. This kind of treatment is called radiotherapy.

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We eat colored food stuffs and use numerous colored materials in our daily life. Because they contain some kind of chemicals in them which are called colorants.

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The uses of colorants by mankind for painting and dyeing dates back to the dawn of civilization. 

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Inorganic pigments such as soot, manganese oxide, and hematite were used as colorants.

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Organic natural colorants have also a timeless history of application, especially for coloring textiles. The organic compounds that are used as colorants are called dyes. These dyes are all aromatic compounds, originating from plants and also from insects, fungi and lichens

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After the evolution of modern organic chemistry, many kinds of synthetic dyes were prepared and used by mankind. Dye chemistry is the study of such kind of dyes. It provides us information on theory, structure, synthesis and applications of synthetic dyes. 

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All colored compounds are not dyes. Dyes are those colored compounds which can be firmly fixed in fabrics by chemical or physical bonding.

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A dye should have the following characteristics:

• It should have a suitable color.
• It should be able to fix itself or be capable of being fixed to the fabric.
• It should be fast to light.
• It should be resistant to the action of water, dilute acids and alkalis.

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Practically all the dyes are synthetic, and are prepared from aromatic compounds obtained from coal tar. Therefore, such dyes are sometimes called as coal tar dyes. But, they may differ in their basic structure and the way of application.

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Dyes are classified in two ways: one, based on the method of application and other based on their parent structure.

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Acid dyes: These are acidic in nature and used for dyeing animal fibers and synthetic fibers. These can be used for protein fibers such as wool and silk. E.g. Picric acid, Naphthol yellow-s

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Basic dyes: These are basic dyes containing basic group (-NH2,- NHR, – NR2). They are used for dyeing animal fibers and plant fibers.

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Mordant dyes or indirect dyes: These dyes have a poor affinity for cotton fabrics and hence do not dye directly. They require pretreatment of the fiber with a mordant.

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Mordant (latin : mordere = to bite) is a substance which can be fixed to the fiber and then can be combined with the dye to form an insoluble complex called lake. 

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Aluminium, chromium, and iron salts are widely used as mordants. E.g. alizarin

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Direct dyes: They have high affinity for cotton, rayon and other cellulose fiber. So, they are applied directly as they fix firmly on the fabric. E.g. Congo red

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Vat dyes: It can be used only on cotton and, not on silk and wool. This dyeing is a continuous process and is carried out in a large vessel called vat. So, it is called as vat dye. E.g. Indigo

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Based on the structure, dyes are classified as: Azo dyes, Diphenyl methane dye, Triphenyl methane dye, Phthalein dye, Anthraquinone dye, Indigo dyes, Phthalo cyanine dye, Nitro and nitroso dyes. 

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Agricultural chemistry involves the application of chemical and biochemical knowledge to agricultural production, processing of raw materials into foods and beverages, and environmental monitoring and remediation. It deals with scientific relation between plants, animals, bacteria and environment.

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Indian chemists and biochemists applied their knowledge and developed modernized agricultural practices which involve use of synthetic fertilizers, genetically modified crops, and equipment’s. It aims at producing sufficient nutritious food and feed the population in a sustainable way while being responsible stewards of our environment and ecosystem.

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Based on the issues and challenges in agricultural production, agricultural chemistry mainly focuses to achieve the following:

• Increase in crop yield and livestock
• Improvement of food quality
• Reducing cost of food production

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Chemical principles and reactions are most widely used in agriculture in order to increase yield, to protect crops from diseases and to simplify the practice of agriculture.

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Soil Testing: Crop lands may have different kinds of soil with varying pH. Soil pH is one of the main criteria to be considered for the selection of crop or remediation of soil. 

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Soil testing involves determination of pH, porosity and texture.

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Chemical Fertilizers: Fertilizers are chemical compounds added to crop field for supplying essential micro and macro nutrients required for crop growth. Ammonium nitrate, calcium phosphate, urea, NPK (Nitrogen, Phosphorous and Potassium), etc. are some of the fertilizers. Depending on the nature of soil, these fertilizers are used singly or as mixtures.

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Pesticides and Insecticides: Crops are prone to diseases caused by pests and insects. Chemically synthesized pesticides and insecticides are used to solve these issues. Chlorinated hydrocarbons, organophosphates and carbonates are used as pesticides and insecticides.

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Food is one of the basic needs of human and animal. The foods we eat also are made of chemicals. Any human might require the three kinds of food.

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Body building foods: These are required for physical growth of body. E.g. Proteins

Energy giving foods: These are the foods that supply energy for the functioning of parts human body. E.g. Carbohydrates  and Fats.

Protective foods: These protect us from deficiency diseases. E.g. Vitamins and Minerals

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Every human requires all these three kind of foods in right proportion for the smooth functioning of the body. The diet that contains all these three foods in right proportion is called Balanced diet.

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Food chemistry is the chemistry of foods which involves the analysis, processing, packaging, and utilization of materials including bioenergy for food safety and quality.

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Goals of food chemistry: The main goal of food chemistry is to cater the needs of quality food to the population in a sustainable way.

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In basic research, food chemists study the properties of proteins, fats, starches, and carbohydrates, as well as micro components such as additives and flavorings to determine how each works in a food system.

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In application research, they often develop new ways to use ingredients or new ingredients altogether, such as fat or sugar replacements.

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Chemicals in Food   we eat in our day to day life contain natural or synthetic chemicals. They serve different functions in human body.

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Nutrients: They are the most essential chemicals present in food. They are required for the growth, physiological and metabolic activities of body. 

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The Nutrients are natural or synthetic. E.g. Carbohydrates, proteins, vitamins and minerals.

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Food additives: These are the chemicals added to food for specialized functions. 

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40% of today’s global population works in agriculture, making it the single largest employment in the world.

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Forensic chemistry applies scientific principles, techniques, and methods to the investigation of crime. 

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In general, forensic chemists work in four steps in the investigation of crime.

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Analysis of evidences: In criminal cases, chemists analyze substances such as blood and DNA to attempt to determine when and by whom the crime was committed.

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Finger print: Finger print is one of the most important evidences in crime investigation. Fingerprints on smooth surfaces can often be made visible by the application of light or dark powder, but fingerprints on cheques or other documents are often occult (hidden).

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Occult fingerprints are sometimes made visible by the use of ninhydrin which turns purple due to reaction with amino acids present in perspiration.

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Fingerprints or other marks are also sometimes made visible by exposure to high-powered laser light. Cyanoacrylate ester fumes from glue are used with fluorescent dyes to make the fingerprints visible.

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Biometrics: The science that involves the study and analysis of human body prints is known as biometrics. The biometric system compares the body prints to the specimen data stored in the system to verify the identity of a person.

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Alcohol test: Drinkers can be easily identified by the use of applied chemistry. The person being tested blows through a tube which bubbles the breath through a solution of chemicals containing sulfuric acid, potassium dichromate, water, and silver nitrate.

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Oxidation of the alcohol results in the reduction of dichromate to chromic ion with a corresponding change in color from orange to green.

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In alcohol test equipment an electrical device employing a photocell compares the color of the test solution with a standard solution, giving a quantitative determination of the alcohol content. The test provides a quick and reproducible determination of the amount of alcohol in a person’s breath and is a numerical measure of the amount of alcohol in the bloodstream.

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Applications of Applied Chemistry

• Many of the advantages of applied chemistry are around us. It is inevitable. 
• Applied chemistry has given us innumerous synthetic materials to lead our day to day life.
• The applied chemistry makes a most important contribution to our society.
• It makes a major contribution to the country’s economic development and plays vital role worldwide.
• The products of applied chemistry are so widespread that they are used in our daily.