The study of Chimestry is very important as it's domain encompasses every sphere of life. Chemists study the properties and structure of substances and the changes undergone by them.
All substances contain matter which can exist in three states- solid, liquid or gas. The constituent particles are held in different ways in these states of matter and they exhibit their characteristics properties.
Matter can also be classified into elements, compounds or mixtures. An element contact particles of only one type which may be a atoms or molecules. The compounds are formed where atoms of two or more elements combine in a fixed ratio to each other.
Mixture occur widely and many of the substance present around us are mixtures.
When the properties of a substance are studied, measurement is inherent. The quantification of properties required a system of measurement and units in which the quantities are the Metric System are widely used. The scientific community, however, has agreed to have a uniform and common system throughout the world which is abbreviated as SI units (International System of Units).
Since measurements involve recording of data which are always associted with a certain amount of uncertainty, the proper handling of data obtained by measuring the quantities is very important.
The uncertainty is taken care of by specifying the number of scientific figures in which the observations are reported. The dimensional analysis helps to express the measure quantities in different systems of units.
Hence, it possible to interconvert the results from one system if units to another.
The combination of different atoms is governed by basic laws of chemical combination - these being the Law of Conservation of Mass, Law of Definite Propertions, Low of Multiple Propertions, Gay Lussac's Law of Gaseous Volumes and Avogadro Law. All these laws led to the Dalton's atomic theory which states that atoms are are building blocks of matter. The atomic mass of an element is expressed relative to isotope of carbon which has as exact value of 12u. Usually, the atomic mass used for an element is the average atomic mass obtained by taking into account the natural abundance of different isotopes of that element. The molecular mass of a molecule is obtained by taking sum of the atomic masses of different atoms present in a molecule.
The molecular formula can be calculated by determining the mass per cent of different elements present in a compound and its molecular mass.
The number of atoms, molecules or any other particles present in a given system are expressed in the terms of Avogadro contact. This is known as 1 mol of the respective particles or entities.
Chemical reaction represent the chemical chat undergone by different elements and compounds. A balanced chemical equation provides a lot of information. The coefficient indicate the molar ratios and the respective number of particles taking part in a particular reaction. The quantitative study of the reactants required or the products formed is called stocihiometry.
Using stoichiometric calulations, the amounts of one or more reactants (s) required to produce a particular amount of product can be determined and vice-versa.
The amount of substances present in a given volume of a solution is and vice- versa. The amount of substance present in a given volume of a solution is expressed in number of ways, e.g, mass per cent, mole fraction molarity and molarity.
