CHEMISTRY

MODELS, SELFEXPLANATORY CHARTS IN BSP

CHEMISTRY A TO Z BRIEF

                         All the matter in the universe is composed of the atoms of more than 100 different chemical  elements,  which are found both in pure form and combined in chemical compounds.  A sample of any given pure element is composed only of the atoms characteristic of that element,  and the atoms of each element  are unique.   For example, the  atoms that constitute carbon are  different  from  those  that  make  up iron,  which are in  turn  different  from  those  of  gold.  Every  element  is designated by a  unique symbol  consisting  of   one,  two, or  three   letters  arising from  either  the currentelement name or itsoriginal  (often Latin)  name.  For example,  the  symbols   for  carbon,  hydrogen,  and  oxygen  are simply C,  H,  and  O, respectively.  The symbol for iron is Fe, from its original  Latin name ferrum.   The fundamental  principle  of  the  science of chemistry  is that the atoms of different elements can combine with one another to form chemical compounds.   Methane, for example,  which  is formed  from the elements carbon and hydrogen in the ratio four hydrogen atoms  for each carbon atom  is  known  to  contain  distinct  CH4 molecules.   The  formula  of  a compound--such as  CH4--indicates the types of  atoms present,  with subscripts representing the relative numbers of atoms (although the numeral 1 is never written).  Water,  which is a chemical compound of  hydrogen and  oxygen in  the ratio  two hydrogen atoms for every oxygen  atom, contains   H2O  molecules.   Sodium  chloride  is  a chemical compound formed from sodium (Na) and chlorine (Cl) in a 1:1  ratio.  Although the formula for sodium chloride is  NaCl, the  compound does not contain actual  NaCl molecules.  Rather,  it contains equal numbers of sodium ions with a charge of positive one (Na+) and chloride ions with a charge of negative one (Cl-). The process  for changing uncharged atoms  to  ions  [i.e., species  with  a  positive  or  negative  net  charge].  The  substances mentioned  above   exemplify   the   two   basic   types  of  chemical compounds:  molecular (covalent)  and  ionic.   Methane  and  water are composed of molecules--that is, they are molecular compounds. Sodium chloride, on the other hand, contains ions -- it is an ionic compound.

                        The  atoms  of the various chemical elements can be likened to the letters of the alphabet:  just  as  the  letters  of  the alphabet are combined to form thousands of words, the atoms of the elements can combine in various ways to form a myriad of compounds.  In fact,  there  are millions of chemical compounds known, and many more millions are possible but have not yet been discovered or synthesized. Most substances found in nature--such as wood, soil, and rocks--are mixtures of chemical compounds.  These  substances  can  be separated into their constituent compounds by physical methods, which are methods that do not change the way in which atoms are aggregated within the compounds. Compounds can be broken down into their constituent elements by chemical changes.   A  chemical  change ( that is,  a chemical  reaction)  is one in which the organization of the atoms is altered.   An example  of  a  chemical  reaction  is  the burning  of  methane  in  the  presence of molecular oxygen (O2) to form carbon dioxide (CO2) and water.  CH4  +  2O2  CO2 + 2H2O  In  this  reaction,  which is an example of a combustion  reaction,  changes occur  in  the  way  that  the  carbon,  hydrogen,  and  oxygen atoms are bound together in the compounds. Chemical compounds show a bewildering array of characteristics. At ordinary temperatures and pressures, some are solids, some are liquids, and some are gases.  The  colours  of  the  various compounds span those of the rainbow. Some compounds are highly toxic to humans, while others are essential for life.  Substitution of only a single atom within a compound may be responsible for changing the colour, odour, or toxicity of a substance. So that some sense can be made out of this great diversity, classification systems have been developed. An example cited above classifies compounds as molecular or ionic.

                         Compounds are also classified as organic or inorganic. Organic compounds, so-called because  many of them were originally isolated from living organisms, typically contain  chains or rings of carbon atoms. Because of the great variety of ways  that  carbon  can  bond  with  itself  and other  elements, there are more than  nine million organic compounds.  The compounds that are not considered to be organic are called inorganic compounds. Within the broad classifications of organic and inorganic  are  many  subclasses,  mainly  based  on  the  specific elements  or  groups  of  elements  that are present.  For example, among the inorganic  compounds,  oxides  contain O2- ions or oxygen atoms, hydrides contain H- ions or hydrogen atoms, sulfides contain S2- ions, and so forth.   Subclasses  of organic  compounds  include alcohols (which contain the -OH group), carboxylic acids (characterized by the -COOH group), amines (which  have  an -NH2 group), and so on.  The  various subclasses of organic and inorganic compounds are described in detail later in this article.

                                             1. ATOMIC STRUCTURE
                                             2. SHAPES OF ORBITS 
                                             3. PERIODIC TABLES
                                             4. CHEMICAL BONDING
                                             5. HYBRIDIZATION TECHNIQUES
                                             6. NITROGEN
                                             7. CARBON
                                             8. UREA CYCLES
                                             9.NUCLEAR FISSION & FUSION REACTION

MANIFACTURAL ILLUSTRATION

                                            Manifactural Illustrations are explains from the Ore to the compund along with the model. BSP contains well equipped and models supported  labaratory and to explain the manifacturing of the compound from their ores in different stages. It is a great opportunity for students and other also to know why the compound will be manifactured and where it will be located (i.e, main form of the compund).  Below mentioned compounds manifacturing are exhibiting in BSP with brief description and thier models.

                                               1. CITRIC ACID
                                               2. BLAST FURNANCE
                                               3. CEMENT
                                               4. COAL TAR
                                               5. SODIUM HYDROXIDE
                                               6. BOMB CALORIMETER

WORKING PRINCIPLES

SAFETY DEVICES LIKE FIRE EXTINGUISHER

                                      Portable or movable apparatus used to put out a small fire by directing onto it a substance that cools the burning material, deprives  the  flame  of  oxygen, or  interferes with  the chemical reactions occurring in the flame. Water performs two of these functions: its conversion to steam absorbs heat, and the steam displaces the air from the  vicinity of the flame. Many simple fire extinguishers, therefore, are small tanks equipped with hand pumps or sources of  compressed gas to propel water through a nozzle. The water may contain a wetting agent to make it more effective against fires in upholstery, an additive to produce a stable foam that acts as a barrier against oxygen, or an antifreeze.

                                   Carbon dioxide is a common propellant, brought into play by removing the locking pin of the cylinder valve  containing  the  liquefied  gas;  this method  has  superseded  the  process, used  in  the  soda-acid  fire extinguisher, of generating carbon dioxide by mixing sulfuric acid with a solution of sodium bicarbonate. Numerous agents besides water are used; the selection of the most appropriate one depends primarily on the nature of the materials that are burning. Secondary considerations include cost, stability, toxicity, ease of cleanup, and the presence of electrical hazard. Small fires are classified according  to  the  nature  of  the  burning  material.  Class A fires involve wood,  paper,  and the like;  Class  B fires involve flammable liquids,  such  as  cooking  fats  and  paint  thinners;  Class C fires are those in electrical equipment; Class D fires involve highly reactive metals, such as sodium and magnesium.  Water  is  suitable  for  putting out fires of only one of these classes (A), though these are the most common. Fires of classes A, B, and C can be controlled by carbon dioxide, halogenated hydrocarbons such as halons, or dry chemicals such as sodium bicarbonate or ammonium dihydrogen phosphate. Class D fires ordinarily are combated with dry chemicals.