Importance Of Chemistry In Technology 5i164s

Report On Importance of Chemistry in Technology

Under Supervision of SKB Faculty IUBAT

Prepared By Md. Shahin Manjurul Alam ID # 07207013 BSME

Submission Date: 27th July, 2010

IUBAT-International University of Business Agriculture & Technology

Importance of Chemistry in Technology Objectives Chemistry is understanding substances and atoms. Everything is made of atoms!!! If it wasn't for chemistry, we couldn't make fire, plastic, everything we have today. Chemistry deals with practically everything (from basic food to complex machinery). From industries to agriculture, chemistry is a foundation to be built. Although most people don't look deeper into it, Chemistry is all around us especially in this age.

First Law of Thermodynamics The branch of chemistry, which deals with energy changes during various physical processes and chemical reactions, is called chemical energetic. All chemical reactions are normally accompanied by energy changes. These energy changes take place because energy is needed to break chemical bonds, and energy is released when new bonds are formed. In the process of chemical reaction, rearrangement of atoms in reactants takes place, to give products. Sometimes, the energy changes associated with the chemical reactions are more significant than the products of the reaction. Most common examples in which energy is given out is combustion of fuels petrol, coal, wood etc. Energy changes accompanying chemical reactions can be in the form of heat, light, mechanical energy, electricity, etc. Therefore, the study of energy changes during chemical reactions is of great importance in our everyday life. It finds a large number of applications not only in chemistry but also in other branches of science, engineering and technology.

Electrochemistry galvanic cells A large number of metals, sodium hydroxide, chlorine, fluorine and many other chemicals are produced by electrochemical methods. The reactions carried out electrochemically can be energy efficient and less polluting. The transmission of sensory signals through cells to brain and vice versa and communication between cells are known to have electrochemical origin. A galvanic cell is an electrochemical cell that converts the chemical energy of a spontaneous redox reaction into electrical energy. In this device the gibbs energy of the spontaneous redox reaction is converted into electrical energy which may be used for running a motor or other electrical gadgets like heater, fan, geyser, etc. Daniel cell is also a type of galvanic cell. The redox reaction of a Daniel cell is:

Zn(s) + Cu2+ (aq) →Zn2+ (aq) + cu (s) This cell converts the chemical energy liberated during the redox reaction to electrical energy and has an electrical potential equal to 1.1 V when concentration of Zn2+ and Cu2+ ions is unity. If an external opposite potential is applied and increased slowly, the reaction continues to take place till the opposing voltage reaches the value 1.1 v. The redox reaction of the cell is a combination of two half reactions whose addition gives the overall cell reaction: i. ii.

Cu2+ + 2e- → Cu (s) (reduction half reaction) Zn (s) → Zn2+ + 2e-

(oxidation half reaction)

These reactions occur in two different portions of the daniell cell. The reduction half reaction occurs on the copper electrode while the oxidation half reaction occurs on the inc electrode. These two portions of the cell are also called half-cells or redox couples. The copper electrode may be called the reduction half cell and the zinc electrode , the oxidation cell.

Applications on Positive Ions Cations Ions are the most important to life. Sodium, potassium and calcium ions are useful in the living organism’s cells, especially in cell membranes. The other applications of ions are that they are used as smoke detectors and used in ion engines which are unconventional technologies.

Production of Nitric Acid Nitric acid is a strong acid and occurs naturally in a combined state as nitrate salt. As with other industrial inorganic acids, nitric acid is hardly of importance in itself but rather as a key intermediate in the production of industrial goods. The history of modern nitric acid production really begins in 1901when W.Ostwald established the ammonia oxidation conditions necessary for high nitrogen oxide yields. The first plants using Ostwald process were started up in the first decade of the 20th century. Since then many improvements have been made by various workers. Milestones include use of larger ammonia combustion units employing flat platinum-rhodium gauzes instead of Ostwald's rolled up platinum gauze strip and the recovery of the heat of reaction for steam raising or electricity generation. The development of strong, affordable, corrosion resistant stainless steel materials of construction made feasible the absorption of nitrogen oxides in water under pressure, thereby reducing the size and cost of absorption

equipment, while the progress in turbo-machinery technology led to adoption of the more energy efficient dual pressure process. From the 1920 onwards, advances in the synthesis of ammonia from hydrogen and atmospheric nitrogen by the Haber-Bosch process have given the Ostwald route to nitric acid an additional boost by lowering its feedstock costs. Nowadays practically all nitric acid is produced by this process

Uses Nitric Acid Although basic chemistry of the nitric acid process has not changed in the last hundred years, today’s highly efficient, compact and environment friendly plants have been developed by a process comparable with the advances made in automobile technology in the same period.

Renewable Energy Renewable energy is a form of non conventional sources of energy. Renewable energy sources are those which can be continuously obtained. It is not like fossil fuels which is rather rapidly depleting due to high usage. Renewable energy sources are also nature friendly, they do not pollute the ecosystem. So they are environmental friendly.

Introduction to form of renewable energy Some sources of form of renewable energy are 1. Solar energy 2. Wind energy 3. Rain 4. Tidal energy 5. Geothermal energy 6. Hydrothermal energy

Solar Energy as Form of Renewable Energy Solar power is an important energy sources of the earth. All the living power directly or indirectly derive the energy from the solar system that is from the sun. Solar power is continuous in some part of the world except for the nights. That means the sunlight is

continuous in all part of the year. The solar energy can be converted into electric energy and heat energy. Most of the fossil fuels are spend in the developing countries for heating purpose. By using solar energy the pollution can be controlled and the fossil fuel can be saved to other useful thing. Technology is need to use the solar power to convert into fuel and to be stored. New types of Batteries are to be invented for storing large amount of energy.

Introduction to Dehydrohalogenation As the name suggest in this reaction there is an elimination of a hydrogen and a halogen atom from the molecule. The starting substrate for such a reaction is an alkyl halide. ││ -C-C ││ HX When heated in presence of base we get elimination of HX and an alkene is formed. In this reaction there are two reaction mechanismsthat compete with one another to give a product and whenever a reaction takes place such that there is competition between two mechanisms as elimination and substitution several factors favour aparticular reaction. For example if we have an alkyl halide R-X, then the primary alkyl halide will undergo elimination rather reluctantly or with difficulty and preferentially substitution(bimolecular takes palce). But the secondary alkyl halide prefers to undergo bimolecular elimination reaction as much as the bimolecular substitution type. Besides this there are other factors governing or influencing this reaction, they are i) Nature of nucleophile: Thus a strong nucleophile and a strong base like OH - influences elimination strongly over substitution. iii) Nature of solvent: A polar solvent favours elimination. iv) High temperature favours bimolecular elimination reaction. v) A polar solvent but low temperature favours formation of alchohol.

vi) A high temperature and a less polar solvent favours bimolecular elimination reaction. The tertiary alkyl halides undergo bimolecular elimination easily than bimolecular substitution reaction. Thus in dehydrohalogenation the most important factor that governs the reaction is the nature of alkyl halide.

Introduction of Colloids In 1986 Thomas Graham which can work for diffusion to be found substances in sugars acids and bases. It can be parchment in a gelatin glue and albumen. These substances belongs to a category of crystalline state are known as crystalloids. Then the substance which belongs to another category is known as colloids. The branch of development the observation is called as a colloidal science.

Importance Types of Colloids The followings are some of the importance types of colloids. 

Lyophobic colloids:

It has a dispersed phase with a little affinity to a dispersed medium in the colloidal solution. 

Lyophilic colloids:

It has a dispersed phase with a considerable affinity to a dispersed medium in the colloidal solution.

Importance Functions of Colloids The followings are some of the importance functions of colloids. 

They are intermediate between suspension and true solutions.

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The colloids can be classified as dispersed phase and dispersed medium.

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A dispersed phase has the substance of distributed in the colloidal particles.

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The dispersed medium has continuous phase with a colloidal particles of dispersed.

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It can be purified by a electro dialysis, dialysis and ultra filtration.

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The lyophobic sols are prepared by special methods and these methods fall into two categories as dispersion methods and condensation method.

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In dispersion method they are splitting the coarse aggregates of a substance into a colloidal size.

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The condensation methods can aggregate very small particles into the colloidal particles.

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In the colloidal dispersions the suspended particles possess either in a positive or a negative charge.

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The colloids have kinetic, optical and electrical property.

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The colloidal substances are across in our daily life process as eating, wearing cloths, live in the house and reading news papers.

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The colloid has two applications were natural and technical.

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The condensation and dispersion are the two methods which can be used for preparation.

Importance of Cannizaro Reaction Importance of the Solvent This reaction can be done with KOH pellets with benzaldehyde in mortar and pestle which clearly indicates the lesser important role of the solvent in the mechanism of the reaction resulting in the formation of carboxylic acid and an alcohol. Thus the role of the base becomes more important in Cannizzaro's reaction. Importance of the reaction Cannizzaro's reaction is observed in aldehydes undergoing hydrolysis and not having an alpha hydrogen atom. It can be used to prepare alcohols and carboxylic acids and though economically not a sound method, this reaction can be used for preparation of alcohols for study purposes.