Chemical reactions and equations

Chemical Reactions

The process in which new substances / products are formed.

Example

Hydrogen reacts with oxygen to form water here hydrogen and oxygen are reactants and the water is product.

Burning of magnesium in air.

2 Mg (s) + O² ➡2MgO (s)

Here magnesium is burnt in air reacting with oxygen present in it forming magnesium oxide.

Note magnesium ribbon is cleaned with sand paper before burning.

In a chemical reaction color change can be take place colour change can take place

• Gas can be evolved

• Colour change can take place

• state changed like solid to gas, gas to liquid etc

• Temperature change may occur

• Precipitate can be formed like Barium sulphate white precipitate

Chemical equations

Simple representation of a reaction with symbol and formulas

example

Balancing a chemical equation

Number of atoms of each elements should remain same before and after reaction due to law of conservation of mass.