Definitions (Chemical Reaction)

CHEMICAL REACTION

Chemical equation: The symbolic representation of an actual chemical change during chemical reaction is called chemical equation.

Reactants: The elements or compound that undergoes chemical change during chemical reaction.

Products: The elements or compounds, which are formed as a result of the chemical change in the reactants is called products.

Word equation: The chemical change that is expressed by writing the names of reactants and products.

Formula equation: The chemical changes that is expressed by using symbols and molecular formula of reactants and products.

Balanced chemical equation: The chemical equation in which the total numbers of atoms of the different elements in the reactants and the products of the chemical equation are equal.

Catalyst: A chemical substance that changes the rate of chemical reaction without itself undergoing any permanent chemical change during chemical reaction is known as catalyst.

Positive catalyst: The catalyst which increases the rate of chemical reaction is called positive catalyst. E.g. MnO₂.

Negative Catalyst: The catalyst which decreases the rate of chemical reaction is called negative catalyst. E.g. Glycerin.

Chemical reaction: A chemical change which involves addition, decomposition, or displacement of atoms or groups of atoms is called chemical reaction.

Combination reaction: The chemical reaction in which two or more than two elements or compounds combined to form a new compound is called combination reaction.

Decomposition reaction: The chemical reaction in which a single molecule or a compound decomposes into two or more than two elements or compounds is called decomposition reaction.

Displacement reaction: The chemical reaction in which an element or a radical of a compound is displaced by another element to form a new substance is known as displacement reaction.

Single Displacement reaction: The chemical reaction in which a more reactive element displaces a less reactive element from its compound is called single displacement reaction. E.g. Zn + CuSO₄ → ZnSO₄ + Cu.

Double Displacement reaction: The chemical reaction in which two reacting compounds exchange their ions in aqueous solution.

Acid base/ Neutralization reaction: The chemical reaction in which an acid reacts with base to form salt and water is called acid base reaction.

Endothermic reaction: The reaction in which heat energy is absorbed from the surrounding is called endothermic reaction.

Exothermic reaction: The reaction in which heat energy is released to the surrounding is called exothermic reaction.

Molecular weight: The sum of the atomic weight of all the atoms of the same or different elements present in a molecule is known as molecular weight.

Promoters: Chemicals used to increase the efficiency of a catalyst are called promoters. E.g. Molybdenum.

Atomic mass unit: The mass which is equal to 1/12^th of the mass of one carbon-12 atom is called a.m.u.

Gram molecular mass: The molecular weight of a substance expressed in terms of gram is called gram molecular weight.

Mole: The amount of substance which consists of same number of particles as the number of atoms in 12 g of carbon-12 is called mole.

Avogadro’s number: The number of particles (atoms, molecules or ions) present in one mole of a substance. Its value is 6.022×10²³.

Rate of chemical reaction: The change in the concentration of any one of the reactant or products per unit time is called rate of chemical reaction.