Basic chemistry

  CLASSIFICATION OF ORGANIC COMPOUNDS Classification of organic compounds based on structure or carbon skeleton  Video link  Organic Compound are divided into two types they are  1. Open chain  2. Closed chain  1. Aliphatic or Open chain compounds : Those compounds in which first & last carbon atoms are not connected with each other. Branched or unbranched chains are possible in these compounds.  For example : Aliphatic or open chain compounds are two varieties in these compounds - Saturated Hydrocarbons :  In such type, adjacent carbon are attached with single bonds. Example - CH 3 –CH 2 –CH 3    General formula of these compounds are C n H 2n+2    These are also called as paraffins (Parum + Affins i.e. little reactivity) because these are less reactive due to absence of 𝝅-bonds. Unsaturated Hydrocarbons : There will be a double bond or a triple bond between any two carbon atoms, CH 2 =CH–CH 3 Propene CH≡C–CH 3 Propyne   General formula is C n H 2n or C n H 2n–2    These a

MENCLATURE OF ORGANIC COMPOUNDS   HISTORY :  In 1675, Nicholas Lemery had devided chemical substances into 3 parts. Mineral substance : which are obtained from minerals. eg. gold, silver, iron etc.  Vegetable substance : which are obtained from vegetables. eg. sugar, citric acid etc.   Animal substance : which are obtained from animals. eg. albumin, gilatin etc. After some time when many of the chemical substance were discovered, it was found that some of them can be obtained from both vegetables and animals. So this classification was failed. So chemical substance were then divided into two parts :            (i) Organic compounds : which are obtained from living organism.            (ii) Inorganic compounds : compounds which are obtained from any other sources except                        living organisms. VFT(Vital Force Theory) :  By Berzelius in 1815. Upto 1815, any organic compound could not be synthesized in lab. So Berzelius suggested that there is a mysterious force in living

  Introduction  Matter is made up of atoms or molecules. The arrangement of these molecules determines the state of matter. There are three recognised state of matter : Solid, Liquid and Gas. Matter can change between states when the temperature or pressure is changed. State changes of matter are physical rather than chemical. Difference between states of matter  GASEOUS STATE  Important properties of gases :  ( i ) Mass : Mass in gm = Moles × Molecular mass.  (i i) Volume : Volume of the gas is the volume of container in which they are filled in.  (iii) Temperature : Temperature of a gas is the measure of kinetic energy of gas.                      Kinetic energy ∝ Temperature ( i v) Pressure : Pressure of gas is defined as the force exerted by the gas on the walls of its container. It is often assumed that pressure is isotropic, i.e. it is the same in all the three directions.  Pressure = Force/ Area   P = Mg/ A = (v× d× g )/A  = (A ×h× d× g)/ A   P = hdg  Where.... h = height of th

  Conductors and non-conductors   ( a ) Non - conductor or insulator : Substances which do not allow electric current to pass through them are called non-conductors or insulators.examples - pure water, ice, glass, rubber etc. ( b ) Conductor :  Substances which allow electric current to flow through them are called conductors. Examples -Metals, Aqueous solution of acids, bases and salts, fused salts and impure water etc. Conductors are of two types : (i) Metallic conductors (ii) Electrolytic conductors or electrolytes. ( i ) Metallic conductors : The conductors which conduct electric current by movement of electrons without undergoing any chemical change are known as metallic conductors.Metals (Cu,Ag,Fe,Al etc), non metals (graphite) and various alloys and minerals are examples. (i i) Electrolytic conductors : Those substances whose water solution conducts the electric current and which are decomposed by the passage of current are called electrolytes. In this case, conduction takes pl

 Modern Periodic table Modern Periodic Law :  The recent work has established that the fundamental property of an atom is atomic number and not atomic weight. Therefore, atomic number is taken as the basis of the classification of the elements. The modern periodic law was given by Moseley, it may be stated as : ''The properties of elements are periodic functions of their atomic number". Modern periodic table is also called long form of the periodic table or Bohr’s table. In this table, the elements are arranged in order of their increasing atomic number. It consists of 4 blocks (s, p, d and f), 18 groups numbered from 1 to 18 and 7 periods numbered from 1 to 7. Short tricks to learn periodic table  Blocks : The periodic table is divided into four main blocks (s, p, d and f) depending upon the subshell to which the valence electron enters into.  (1) Elements of group 1 and 2 constitute s-Block.   (2) Elements of group 13, 14, 15, 16, 17, 18 constitute p-Block.   (3)

  Atomic number, Mass number and Atomic species Atomic number or Nuclear charge  (i) The number of protons present in the nucleus of the atom is called atomic number (Z).  (ii) It was determined by Moseley as,  V 1/2  =a(z-b) Where, v=X -  ray’s frequency  Z= atomic number of the metal a & b are constant.  (iii) Atomic number = Number of positive charge on nucleus = Number of protons in nucleus = Number of electrons in nutral atom.  (iv) Two different elements can never have identical atomic number.  Mass number  Mass number (A) = Number of protons or Atomic number (Z) + Number of neutrons or Number of neutrons = A – Z .  (i) Since mass of a proton or a neutron is not a whole number (on atomic weight scale), weight is not necessarily a whole number.  (ii) The atom of an element X having mass number (A) and atomic number (Z) may be represented by a symbol,  Z X A Different types of atomic species Isotopes Given by Soddy 1.They are the atoms of a given element  which have the s

INSIDE THE ATOM   John Dalton 1808, believed that matter is made up of extremely minute indivisible particles, called atom which can takes part in chemical reactions. These can neither be created nor be destroyed. However, modern researches have conclusively proved that atom is no longer an indivisible particle. Modern structure of atom is based on Rutherford’s scattering experiment on atoms and on the concepts of quantization of energy. Composition of atom It is now believed that the atom consists of several sub-atomic particles like electron, proton, neutron, positron, neutrino, meson etc. Out of these particles, the electron, proton and the neutron are called fundamental subatomic particles and others are non-fundamental particles. Fundamental subatomic particles in an atom.  Particle Mass  Charge  Location  P roton   1 amu  +1  In the nucleus   Neutron  1 amu   0

Bases Substances with bitter taste and give a soapy touch are known as bases but many bases have corrosive nature. So bases are defined as "  According to Arrhenius : those substances which give hydroxide or hydroxyl ion (OH - ) in their aqueous solution" are called bases. Properties of Bases The following are the characteristic properties of bases:  1. Taste and Touch  Bases have a bitter taste and their solutions are soapy to touch. 2. Action on indicators . The colours shown by three commonly used indicators in presence of bases are listed below for easy recall.    colours of some common indicators in basic solution  Indicator  colour in basic medium    1. Litmus  Blue    2. Phenolphthalein  Pink    3. Methyl orange  Yellow   3.Conduction of electricity and dissociation of bases  Aqueous solutions (solution in water ) of basesconduct electricity which is due to the forma