CHEMICAL REACTIONS AND EQUATIONS

 

CHEMICAL REACTIONS 

When a chemical change happens, chemical composition of a matter changes and a new product is formed. Whenever a chemical change occurs, we can say that a chemical reaction take place.

In the above picture we can observe that A react with B and produce a new product AB. 

A+B—> AB

substances that take part in reaction are called REACTANTS and the new substances produced as the result of reaction are called PRODUCTS.

Example:- When magnesium burns in air it will react with oxygen to form a white coloured ash magnesium oxide.

Magnesium + Oxygen——> magnesium oxide 

Reactants— magnesium and oxygen 

Product.   — magnesium oxide 

CHEMICAL EQUATIONS

A chemical reaction can be expressed symbolically using chemical equations

eg: magnesium burns in air to form magnesium oxide can be represented as

Mg + O₂−−>MgO

(where magnesium and oxygen are reactants and magnesium oxide is the product)

The physical state of reactants and products is mentioned to make chemical reactions more informative. To represent solid we use (s) for liquid (l) for gas (g) and for aqueous (aq )

Mg(s) + O₂(g)−−>MgO(s)

(REACTANTS are written on the left-hand side(LHS) with a +sign between them and PRODUCT are written on the right-hand side(RHS) and an arrow is placed between them)