Question

how can we Express chemical reactions​

Answer 1

Answer:

The chemical equations can be written by using the symbols of the elements which is involved to express chemical reactions in the shortest way. For example, the reaction of hydrogen and oxygen forms water is expressed as Hydrogen+ Oxygen Water. This can be expressed in the shortest way by using symbols for hydrogen, oxygen and water as:

Answer 2

Chemical changes are the changes in which new products are formed. It involves breaking of old chemical bonds and establishment of new ones.

How can we represent chemical changes ?

Chemical changes can be represented by writing them as a chemical equations. Chemical  equations can be written in two ways :

1. Word Equation : Here, the name of the elements and compounds  are written in words and the reactants and products are separated by an arrow and the reactants and products have a '+' sign between them.  For example, Magnesium + Oxygen -----> Magnesium Oxide.
2. Symbolic Equation: Here, the symbols of the elements and compounds are written. Products and reactants are separated by an arrow between them. Reactants and products have a '+' sign between them.

Rules for writing a chemical equation:

1. Reactants and products have an arrow between them
2. The various reactants and products have a '+' sign between them.
3. The conditions and catalyst if any need to be mentioned above and below the arrow.
4. They can be made more informative by mentioning the stated of the reactants and products.

For example,

2Mg (s) + O₂ (g) -------(Δ)------> 2MgO (s)

Here (s) , (g) indicate the state of the reactants and products. The delta (Δ) above the arrow indicates that magnesium was heated in presence of oxygen .