SOME BASIC CONCEPTS OF CHEMISTRY
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UNIT 1
SOME BASIC CONCEPTS OF CHEMISTRY
After studying this unit, you will be able to
• understand and appreciate the role of chemistry in different spheres of life;
• explain the characteristics of three states of matter;
• classify different substances into elements, compounds and mixtures; • define SI base units and list some commonly used prefixes;
• use scientific notations and perform simple mathematical operations on numbers;
• differentiate between precision and accuracy; • determine significant figures;
• convert physical quantities from one system of units to another;
• explain various laws of chemical combination; • appreciate significance of atomic mass, average atomic mass, molecular mass and formula mass; • describe the terms – mole and molar mass;
• calculate the mass per cent of different elements constituting a compound; • determine empirical formula and molecular formula for a compound from the given experimental data;
• perform the stoichiometric calculations. 1
Chemistry is the science of molecules and their transformations. It is the science not so much of the one hundred elements but of the infinite variety of molecules that may be built from them ...
Roald Hoffmann
Chemistry deals with the composition, structure and properties of matter. These aspects can be best described and understood in terms of basic constituents of matter: atoms and molecules. That is why chemistry is called the science of atoms and molecules. Can we see, weigh and perceive these entities? Is it possible to count the number of atoms and molecules in a given mass of matter and have a quantitative relationship between the mass and number of these particles (atoms and molecules)? We will like to answer some of these questions in this Unit. We would further describe how physical properties of matter can be quantitatively described using numerical values
with