UNIT 1.1 CHEMISTRY

LEC: 1                           CHEMISTRY

Chemistry, a branch of physical science, is the study of the composition, properties and behavior of matter.

Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds. 

Chemistry is also concerned with the interactions between atoms (or groups of atoms) and various forms of energy (e.g. photochemical reactions, changes in phases of matter, separation of mixtures, properties of polymers, etc.)

chemistry are generally classified in three types:

PHYSICAL CHEMISTRY: Physical chemistry is the branch of chemistry that is concerned with the application of physics to chemical systems. it covers following topics:-

• Structure of Atom
• States of Matter
• Thermodynamics
• Equilibrium
• Solutions
• Electrochemistry
• Chemical Kinetics

INORGANIC CHEMISTRY: Inorganic chemistry related with inorganic compounds, It covers with the formulation, attributes and responses of all chemical elements and their chemical compounds. it covers following topics:-

• Classification of Elements and Periodicity in Properties
• Chemical Bonding and Molecular Structure
• Hydrogen
• The s-Block Elements
• The p-Block Elements
• The p-Block Elements
• The d-and f-Block Elements
• Coordination Compounds

ORGANIC CHEMISTRY: is a branch of chemistry that concerned structure and behavior of those molecules, which are composed of only a few different types of atoms like carbon, hydrogen (hydrocarbons), oxygen, nitrogen, and a few miscellaneous others. it covers following topics:-

• Basic Principles and Techniques of Organic Chemistry
• Hydrocarbons
• Haloalkanes and Haloarenes
• Alcohols, Phenols and Ethers
• Aldehydes, Ketones and Carboxylic Acids
• Amines

there are some more types of division of chemistry like Analytical chemistry ( identification and quantification of materials in a mixture), Biochemistry (study of biological system), Nuclear chemistry, Polymer chemistry etc.

MATTER

Anything which has mass and occupies space is called matter. 

matter are classified on the basis of 
2) Microscopic View: the properties of matter studied at molecular level by considering all molecules and atoms. matter can be classified on the basis of microscopic view in three categories

• SOLID: have definite volume and definite shape because particles are held very close to each other in an orderly fashion and there is not much freedom of movement.
• LIQUID: have definite volume but not the definite shape they take the shape of the container in which they are placed because the particles are close to each other but they can move around.
• GASES: have neither definite volume nor definite shape. They completely occupy the container in which they are placed because particles are far apart as compared to those present in solid or liquid states and their movement is easy and fast.

fig: states of matter

2) Macroscopic View: properties observed from human senses like touch or by naked eyes, without observation of all molecules and atoms.

now on the basis of Macroscopic view matter are classified as

Fig 2: Classification of Matter on the basis of macroscopic view.

MIXTURE: A mixture contains two or more substances present in it (in any ratio) which are called its components. A mixture may be homogeneous or heterogeneous. 

In a homogeneous mixture, the components completely mix with each other and its composition is uniform throughout. Sugar solution, and air are thus, the examples of homogeneous mixtures. 

In heterogeneous mixtures, the composition is not uniform throughout and sometimes the different components can be observed. For example, the mixtures of salt and sugar, grains and pulses along with some dirt (often stone) pieces, are heterogeneous mixtures.

PURE SUBSTANCES: Pure substances have fixed composition. Copper, silver, gold, water, glucose are some examples of pure substances. Glucose contains carbon, hydrogen and oxygen in a fixed ratio and thus,like all other pure substances has a fixed composition. Also, the constituents of pure substances cannot be separated by simple physical methods.

Pure substances can be further classified into elements and compounds.

ELEMENT: it consists of only one type of particles. These particles may be atoms or molecules. You may be familiar with atoms and molecules. Sodium, copper, silver, hydrogen, oxygen etc. are some examples of elements.  

Some elements such as sodium or copper, contain single atoms held together as their constituent particles whereas in some others, two or more atoms combine to give molecules of the element. Thus, hydrogen, nitrogen and oxygen gases consist of Molecules in which two atoms combine to give their respective molecules.

atoms is not stable in nature so they present in the form of stable molecules or compound.

When two or more atoms of different elements combine, the molecule of a compound is obtained. The examples of some compounds are water, ammonia, carbon dioxide, sugar etc.