Chemistry is the study of pure science that deals with the physical or chemical properties, reactions, composition, and structure of atoms, ions, or molecules that interact with energy. During any chemical transformation, an atom or molecule of matter absorbed or emitted energy. Chemistry provides the properties and structure of atoms of the periodic table elements. Learning chemistry suggests how new chemical compounds (inorganic or organic compounds) are formed from different types of atoms by chemical bonding like ionic bonding, covalent bonding, or metallic bonding.
Branches of Chemistry
Physical, inorganic, organic, environmental, and analytical chemistry are the basic branches of chemistry for the different classes of study of properties, composition, structure, and chemical reactions in science.
What is inorganic chemistry?
Inorganic chemistry is the study of the properties, composition, reactions, and formation of inorganic compounds by different types of atoms of the chemical elements. In this part, we discuss the properties of chemical elements or compounds which is closely related to their electronic configuration. Orbital hybridization, molecular orbital theory, and crystal field theory have given a clear understanding of modern inorganic compounds.
Organic chemistry is the study of properties, composition, and chemical reactions of organic compounds coming mainly from living organisms. Simply, it is the chemistry of carbon compounds. This definition included the compounds like carbon monoxide, carbon, carbon dioxide, carbonates, and carbon disulfide, etc. But these compounds are usually studied in inorganic textbooks. Therefore, it is the study of hydrocarbons and hydrocarbon-related compounds.
The empirical formula in chemistry defines the relative number of each class of atom in the general molecular formula that helps for the calculation of percentage composition or chemical structure of the molecule or compound.
Question: If 0.202 gm of an organic compound gave on combustion 0.361 gm of carbon dioxide and 0.147 gm of water. How to find the empirical formula of the compound in chemistry?
Answer: Weight of carbon in the said compound = (12/44) × 0.361 gm = 0.0985 gm, weight of the hydrogen = (2/18) × 0.147 = 0.0163 gm, and weight of oxygen = 0.202 – (0.0985 + 0.0163) = 0.0872 gm.
Therefore, the ratio of molar mass of carbon, hydrogen, and oxygen atom or C : H : O = (0.0985/12) : (0.0163/1) : (0.0872/16) = 3 : 5.98 : 2. From the above solution, the empirical formula of said organic compound in chemistry, C3H6O2.
Molecular weight determination
The molecular formula provides the actual number of atoms present in each kind of molecule. It is obtained by multiplying the empirical formula by some whole number which is obtained from the consideration of the molecular weight of the compounds. In most cases, it is one. The methods used for the determination of molecular weight are,
These methods are described fully in the physical chemistry textbooks. But other physical methods like Graham’s law of diffusion, sedimentation, the viscosity of liquid and gases, osmotic pressure, X-ray radiation analysis, mass or atomic spectrum are used for substances that contain high molar mass.
Physical chemistry is the study of general definition, law, principle, and mathematical equations, or formulas related to the atom or molecule of matter. Therefore, physical chemistry deals with the topics related to solid (amorphous and crystalline solid), gas (ideal and real gas, critical temperature), liquid, thermodynamics law of energy conservation, heat (molar or specific heat), chemical equilibrium, chemical kinetics, chemical catalyst, etc. The study of physical chemistry is incomplete if the student confines himself only to the theoretical information, he must gain the practical explanations of the theory, definition, problem, and solution.
Analytical chemistry is the study or analysis of the chemical formula, structure, composition of the atom, molecule, or matter for chemical, forensic, medicinal, food science, or technology. However, modern analytical chemistry definitions help to identify general substances that function on composition, structure, and reaction analysis for different types of chemical substances. Therefore, the most difficult task for an analytical chemist is to explain what is the nature of analytical chemistry? It is an interdisciplinary branch of science where a large number of research works have been contributed to its development.
All chromatographic studies in chemistry were invented by biochemists or biological scientists, while methods of the electromagnetic spectrum and mass spectroscopy were discovered by physicists. But if we close look, the different types of research topics published in a different set of science journals by using analytical chemistry methods, about 60% of such materials are published by persons who are not analytical chemists in the true sense.