CHEMICAL REACTIONS

1. What is chemical reaction?
- The breaking down of the old chemical bond and formation of a new chemical bond so as to form new substances with new properties is known as chemical reaction.

2. Define word equation, formula equation and balanced chemical equation. 
- Word equation is defined as an equation in which  the name of chemical substances is written.
Example: Hydrogen+oxygen------> water
- Formula equation is defined as an equation of a chemical reaction expressed in short form by a chemical formula.
- Example: H₂  +  O₂ ------>  H₂O
-Balanced chemical equation is defined as an equation in which the total number of each element in the reactants and products are equal is called a balanced chemical equation.
- Example:  2H₂  +  O₂ ------>  2H₂O

3. What are the factors affecting chemical reaction?(any 4)
- The factors effecting chemical reaction are:
1. Contact- When substance comes in direct contact chemical reaction occurs.
2. Heat- It increases K.E. and hence, increases capacity by colliding with other atom.
3. Light- Light energy makes the reacting atoms reactive and helps to react faster.
4. Catalyst- The chemical substance which increases or decreases the rate of chemical reaction is called a catalyst. A promoter increases power of catalyst.