Prabin Kalikote

A chemical reaction in which a single reactant isbroken down into two or more products called adecomposition reaction.For example:

CaCO₃ -------> CaO + CO₂
CuCO₃ -------> CuO +CO₂

A chemical reaction in which two or more reactantsare combined together to give a single product is calleda combination reaction.Examples are:

C + O₂ --------> CO₂
C + 2H₂ ---------> CH₄

A catalyst is a chemical substance that increases ordecreases the rate of a chemical reaction without takingpart in a chemical reaction.

The +ve catalyst is the chemical substance thatincreases the rate of a chemical reaction. For example MnO₂.Thecatalyst is the chemical substance thatdecreases the rate of a chemical reaction. For exampleglycerine.

Four factors that bring about a chemical change are:

> Heat > Catalyst
> Light >Solution
> Pressure > Electricity

Any 4 limitations of balanced chemical eqn are:

1. The physical estate of reactants and products.
2. The concentration of reactants.
3. The rate of the chemical reaction.
4. The time is taken to complete the reaction.

Anythree pieces of info that can be obtained froma balanced chemical eqn are:

1. The type of chemical reaction.
2. The name and symbol of reactants and products.
3. The total number of atoms of reactants and products.

A chemical eqn. which contains an equal number ofatoms of each element in both reactant and productside is called balanced chemical eqn.

Example: 2H₂ + O₂ --------> 2H₂O