Introduction to Chemistry PDF

Pharmacy dept. Theoretical organic chem. Dr. Shilan Ali Introduction to Chemistry What is Chemistry? Chemistry is the study of the nature, properties, and composition of matter, and how these undergo changes What...

Pharmacy dept. Theoretical organic chem. Dr. Shilan Ali Introduction to Chemistry What is Chemistry? Chemistry is the study of the nature, properties, and composition of matter, and how these undergo changes What is matter? Matter is anything which has mass and occupies space. Iron, gold, milk, aspirin, monkeys and rubber, these are all matter. Organic Chemistry : Organic chemistry is a scientific study of the structure, properties, and reactions of organic compounds and organic materials, i.e., matter in its various forms that contain carbon atoms. Natural compounds : refer to those that are produced by plants or animals. Synthetic compounds: Compounds that are prepared by reaction of other compounds are referred to as "synthetic". The concept of functional groups Functional groups can have decisive influence on the chemical and physical properties of organic compounds. Molecules are classified on the basis of their functional groups. Alcohols, for example, all have the subunit C-O-H. Organic reactions: are chemical reactions involving organic compounds. Many of these reactions are associated with functional groups. The basic reaction types are: addition reactions, elimination reactions, substitution reactions, rearrangement reactions and redox reactions. 1 Page Lecture 1 Pharmacy dept. Theoretical organic chem. Dr. Shilan Ali Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent making four electrons available to form covalent chemical bonds. Carbon needs eight electrons to satisfy its valence shell. Carbon therefore forms four bonds with other atoms (each bond consisting of one of carbon's electrons and one of the bonding atom's electrons). 2 Page Lecture 1 Pharmacy dept. Theoretical organic chem. Dr. Shilan Ali Molecules All substances are made up of molecules which are collections of atoms. All the molecules in existence are made up of about a hundred different kinds of atoms. For example, a water molecule is composed of two atoms of Hydrogen and one atom of Oxygen. We write its formula as H2O. A molecule of Sulphuric Acid contains two atoms of Hydrogen, one atom of Sulphuric and four atoms of Oxygen. Its formula is H2SO4. Chemical bond: A chemical bond is an attraction between atoms or molecules that allows the formation of chemical compounds, which contain two or more atoms. Covalent bonding: is a common type of bonding, in which the electronegativity difference between the bonded atoms is small. Bonds within most organic compounds are described as covalent. 3 Page Lecture 1 Pharmacy dept. Theoretical organic chem. Dr. Shilan Ali Ionic bonding: is a type of electrostatic interaction between atoms which have a large electronegativity difference. Intermolecular bonding: A large difference in electronegativity between two bonded atoms will cause dipole-dipole interactions. Hydrogen bonding: A hydrogen bond is an attraction between two atoms that already participate in other chemical bonds. One of the atoms is hydrogen, while the other may be any electronegative atom, such as oxygen, chlorine, or fluorine. Hydrogen bonds may form between atoms within a molecule or between two separate molecules. 4 Page Lecture 1