Chemical Reaction and Equations
Exothermic and Endothermic reactions
A chemical reaction which is accompanied by evolution of heat energy is known exothermic reaction.
A chemical reaction which is accompanied by absorption of heat energy is known as endothermic reaction.
A skeletal equation equation is an equation in which various reactants and products are represented by their respective formulae but no attempt is made to equation the number of atoms of various elements on both the sides of the equation.
Balanced chemical equation
An equation in which number of atoms of each elements is equal on both the sides of the equation is known as balanced chemical equation.
Types of chemical reactions
Double displacement reaction.
Oxidation and Reduction.
The reactions in which two or more substances combine to form a single new substance are called combination or synthesis reactions.
The decomposition reaction generally take place when energy in some form such as heat, electricity or light is supplied to the reaction.
The chemical reactions in which one element displaces another element from a compound and takes it’s place are known as displacement reactions.
Double displacement reaction
The reactions in which two compounds react to form different compounds by mutual exchange of ions called double displacement reactions.
Oxidation and Reduction ( redox reaction)
Oxidation is a process of addition of oxygen or removal of hydrogen to a substance.
Reduction is a process of removal of oxygen or addition of hydrogen to a substance.
Oxidising and Reducing agents
A substance that brings about oxidation, i.e., addition of oxygen or removal of hydrogen, is called oxidising agent.
A substance that brings about reduction i.e., removal of oxygen or addition of hydrogen, is called reducing agent.
The reactions in which rearrangements of atoms within molecules of a substance, takes place resulting in the formation of a new substance are known as isomerization reactions. The product formed as a result of isomerization reaction has same molecular formula as the reactant but has different molecular structure.
The process of slow conversion of metals into their undesirable compounds( usually oxides) by reaction with moisture and other gases present in the atmosphere is called corrosion of metals. Corrosion of metal is an oxidation process.
The food material containing fat or oil develop a disagreeable odour and taste when left exposed to warm moist air a long time. This is called rancidity. Rancidity caused due to hydrolysis and oxidation.
In order to minimize rancidity due to oxidation certain substance which prevent oxidation are added foods containing oils and fats. Such substance can be slowed down by storing of food items containers and by flushing out air with some of gas like nitrogen.