Hello friends, welcome in this website. In this article, we shall discuss about some basic concepts of chemistry. As we all know that this chapter is very important to study the whole chemistry. i think, we shall must read this chapter throughout. We shall study all the important topics which have been included in this chapter
Some important terms to be used in some basic concepts of chemistry
Atom: the smallest part of any substance which has no existence but takes part in chemical reactions is called an atom. For example H of H2, C and O of CO2 etc.
Molecule: The smallest part of any substance which has existence but does not take part in any chemical reactions is called molecule. For example O2, CO2, H2O etc.
Matter: Any substance in the universe which has mass and occupies space is called matter. And specific kind or product of any matter is called substance. For example wood is a matter and its product like chair, table, door, cots are substances.
Kinds of matter: In some basic concepts of chemistry
Matters have been classified on the following basis:
Physically, There are three types of matter.
- Solid. A matter which has definite shape and definite volume is called solid. Example wood, stone, iron, gold, ice etc.
- Liquid. A matter which has definite volume but indefinite shape is called liquid. For example milk, blood, oil, bromine, mercury etc.
- Gas. A matter which has indefinite volume and indefinite shape is called gas. For example air, oxygen, nitrogen, carbon dioxide, ammonia etc.
Chemically, There are three types of matter: In basic concept of chemistry
Element. A matter that is made of only one type of atoms is called element. Example sodium, potassium, hydrogen, oxygen etc. Nowadays, there are about 114 elements are known.
Elements have been further classified into three categories as following
- Metal. An element which has tendency to loss of electrons is known as metal. for example sodium, potassium, copper, silver, gold etc.
- Non-metal. An element which has tendency to gain of electrons is known as non-metal. for example hydrogen, nitrogen, oxygen, helium, sulphur etc.
- Metalloid. An element which behaves both like metals and non-metals is called metalloid. for example arsenic, antimony, bismuth, tellurium, selenium, silicon, boron.
Compound. A matter that is made of two or more types of atoms after chemical combination in a fixed ratio is called compound. Example water is made of hydrogen and oxygen in 2:1 ratio.
Compounds have been further classified into two parts as following
- Inorganic compound. Those compounds which are obtained from rocks, salts or minerals are called inorganic compounds. Examples, sodium chloride, caustic potash, potash alum, borax etc.
- Organic compounds. All the hydrocarbons and there derivatives are known as organic compounds.
Important Hydrocarbons are methane, ethane, ethylene, acetylene, benzene which are made of only hydrogen and carbon atoms.
Methyl alcohol, methyl chloride, methyl amine are considered as derivatives of methane.
Mixture. A matter that is made of two or more kind of unreacting substances in any ratio is called mixture. There are two types of mixtures:
- Homogeneous mixture- A mixture in which all the components or constituent particles are equally distributed in the whole mass is known as homogeneous mixture. Examples all the solutions are example of homogeneous mixture.
- Heterogeneous mixture- A mixture in which all the components or constituent particles are distributed in different manners is called heterogeneous mixture. Example colloids and suspensions are example of heterogeneous mixture.
Radicals: The atom or group of atoms which carry charges is called radical. example H+, NH4+, H3O+, NO3–, Cl– etc.
Types of radicals: There are two types of radicals in some basic concept of chemistry.
- Positive radicals or basic radicals: those radicals which carry positive charges are called basic radicals. Example Na+, Mg2+, NH4+, Ca2+
- Negative radicals or acidic radicals: those radicals which carry negative charges are called acidic radicals. Example Cl–, OH–, CN–, Br–, SO42-
Unit and conversion in some basic concepts of chemistry:
There are three kinds of units in some basic concepts of chemistry.
1. Fundamental unit
2. Derived unit
3. Subsidiary unit
Fundamental or basic unit: those units which are independent called fundamental units. Example metre, kilogram, Kelvin. There are 7 basic units in S.I. system. They are followings 
Derived units: those units which are formulated with the help of basic units are called derived units. Example unit of area as m2. Unit of velocity as Ms-2.
Subsidiary units: the terms which are used before basic units to show higher or lower value of these units are called subsidiary units. Example in centimeter, centi is subsidiary unit and metre is a basic unit.
Important details of terms to be used as subsidiary units: 
Laws of chemical combinations in some basic concepts of chemistry:
1. Law of conservation of mass. This law was introduced by Antoine Lavoisier. According to this law, the mass of the reactants is equal to the mass of the products in a chemical reaction.
2. Law of definite proportions. This law was proposed by Joseph Proust. According to this law, a given compounds always contains the same proportion of elements by weight whether it is obtained from any sources.
3. Law of multiple proportions. This law was introduced by Dalton. He stated that if two elements combine to form more than one compound, the masses of one element that combine with a fixed mass of the other element, are in the ratio of small whole numbers.
4. Gay Lussac’s Law of Gaseous Volumes. This law was given by Gay Lussac. He observed that when gases combine or are produced in a chemical reaction they do so in a simple ratio by Volume at the same temperature and pressure.
5. Avogadro ‘s Law. Avogadro proposed that equal volume of all gases at the same temperature and pressure should contain equal number of molecules.
6. Dalton’s Atomic Theory. Dalton’s atomic theory was proposed in the following ways.
1) Matter consists of indivisible atoms.
2) All atoms of a given elements have identical properties, including identical mass. Atoms of different elements have different mass.
3) Compounds are formed when atoms of different elements combine in fixed ratio.
4) Chemical reactions involve reorganisation of atoms. These are neither created nor destroyed in a chemical reaction.
Atomic mass in basic concepts of chemistry.
Atomic mass.
It is the number which implies that the mass of an atom of any element is how much heavier than the 1/12 th mass of an atom of C12- isotope.
Average atomic mass:
The sum of the product of the atomic mass and fraction of occurrences of each element is called average atomic mass. Average atomic mass = ∑ fi . Ai where fi = fraction of occurrences of isotopes and Ai = atomic mass of each isotopes.
Gram atom : when atomic mass of any element is expressed in Gram. It is called Gram atom. Example 1 gram atom Na = 23 g Na.
Molecular mass It is a number which implies that the mass of an molecule of any element or compound is how much heavier than the 1/12 th mass of an atom of C12- isotope.
Gram molecule. When molecular mass of a molecule is expressed in Gram, it is called gram molecule. Example 1 gram molecule oxygen = 32 g oxygen (O2).
Physical qualities Basic units Symbols of unit
Mole. The amount of a chemical substance which contains 6.022 × 1023 constituent particles (atoms, molecules or ions), it is called a mole of this substance.
1 mole Na = 6.022 × 1023 atoms of Na.= 23 g Na = 1 g atom of Sodium.
1 mole CO2 = 6.022 × 1023 molecule of CO2. = 44 g CO2 = 1 g molecule of carbon dioxide.
Molar Volume. The Volume of 1 mole of any gas at STP or NTP is 22.4 L. This Volume is called molar Volume. Example 1 mole of O2 at STP = 22.4 L O2. 1 mole of CO2 at STP = 22.4 L of CO2.
Concentration in solution
The amount of any component in the certain amount of solution is called the concentration of solution. Ex:- 5M of Sulphuric acid in aqueous solution is the concentration of the solution.
Various ways to represent concentration of solution in some basic concepts of chemistry
1. By percentage
2.By molarity
3. By molality
4. By normality
5. By mole fraction
6. By ppm
1. By percentage. The mass or Volume of any component present in per 100 g or ml of solution is called concentration by percentage
By this way, concentration can be represented as.
A. % (w/w)
B. % (w/v)
C. % (v/v)
2. Molarity. Number of moles of a solute present in per litre solution is called molarity. Its unit is molL-1 or M.
3. Molality. Number of moles of a solute present in per kilogram of solvent is called molality. Its unit is mol/Kg or m.
4. Normally. Number of g- equivalent of a solute present in per litre of solution is called normality. Its unit is g-eqL-1.
5. Mole fraction. The number of moles of any component present in per mole of solution is called mole fraction of this component. It is denoted by ‘x’. It is dimensionless.
6. Ppm( parts per million part). The part of a solute by mass present in million part of solvent or solution is called ppm.
Stoichiometry: in some basic concepts of chemistry
The measurement of the amount any component participating in a reaction with the help of balanced chemical equation is called stoichiometry. This method is applied to know either mass, mole or Volume of any component.
Percentage of any element in a compound.
In some basic concepts of chemistry, the mass of any element present in per 100 gram of any compound is called percentages of the elements. Example in Urea the percentage of C, N, H and O are 20%, 46.66%, 6.67% and 26.67% respectively.
Formula in some basic concepts of chemistry:
The symbolic representation of one molecule of the substance which tells the number and kinds of atoms of various elements present in its molecule.
Types of formulas in some basic concepts of chemistry:
1. Empirical formula. The chemical formula which expresses simplest whole number ratio of the atoms of the various elements present in one molecule of the compound. Ex:- CH2O is the empirical formula of Glucose.
2. Molecular formula. The chemical formula which represents the actual number of atoms of various elements present in one molecule of the compound. Ex:- C6H12O6 is the molecular formula of Glucose.
Relation between empirical formula and molecular formula:
Molecular formula = n × empirical formula. Where n is an integer such as 1, 2, 3 —- etc. and
n = Molecular mass/ Empirical formula mass.
Molecular mass = 2 × vapour density. (By Victor Meyer’s method)
Calculation of the empirical formula in some basic concepts of chemistry
The following steps are involved in the calculation of the empirical formula.
1. Convert the mass percent into grams.
2. Calculate the number of moles.
3. Calculate the simplest molar ratio.
4. Calculate the simplest whole number ratio.
5. Now write the empirical formula.
Balancing of a chemical reaction in some basic concepts of chemistry:
The following methods are generally used for balancing of chemical equations:
1. Hit and trial method
2. Partial equation method
3. Oxidation number method
4. Ion-electron method
1. Hit and trial method. The following steps generally help to balance the equation:
Step 1. Write down the Skelton equation by writing the correct formula of the reactants and the products.
Step 2. Start the balancing by multiplying with suitable numbers in each of the formulas of reactants and products so that atoms of each elements be equal in both side of the Skelton equation.
Step 3. You can start by selecting the biggest formula either of the reactant or product.
Step 4. When an elementary gas (diatomic) appears as a reactant or a product, write them in atomic state to balance easily.
2. Partial equation method in some basic concepts of chemistry
When same element is repeated in a number of compounds, partial equation method is more helpful. This method involves the following methods-
1. The chemical reaction represented by the equation is supposed to proceed in two or more steps.
2. The Skelton equations representing each steps are written and then balanced by hit and trial method.
3. If necessary, the partial equations are multiplied by suitable integers so as to canceal intermediate products which do not occur in the final equation.
4. finally, the partial equations are added up to get the final balanced equation.