Chapter 1: Chemical Reactions and Equations
Easy Notes for Class 10 Science
What is a Chemical Reaction?
In our daily life, many changes take place around us. Milk turns into
curd, iron gets rusty, and food gets cooked. These changes happen
because substances are transformed into new substances. Such a
process is called a chemical reaction.
A chemical reaction is a change in which one or more substances are
converted into different substances with new properties.
How Can We Identify a Chemical Reaction?
A chemical reaction usually shows one or more of the following
signs:
A change in colour
Release of a gas
Formation of a solid substance (precipitate)
Change in temperature
Change in smell
Chemical Equations
Scientists use chemical equations to represent reactions in a short
and simple way.
Example:
Magnesium + Oxygen → Magnesium Oxide
Balanced equation:
2Mg + O₂ → 2MgO
A balanced equation has an equal number of atoms on both sides.
Types of Chemical Reactions
Combination Reaction
When two or more substances join together to form a single
product, it is called a combination reaction.
Easy Notes for Class 10 Science
What is a Chemical Reaction?
In our daily life, many changes take place around us. Milk turns into
curd, iron gets rusty, and food gets cooked. These changes happen
because substances are transformed into new substances. Such a
process is called a chemical reaction.
A chemical reaction is a change in which one or more substances are
converted into different substances with new properties.
How Can We Identify a Chemical Reaction?
A chemical reaction usually shows one or more of the following
signs:
A change in colour
Release of a gas
Formation of a solid substance (precipitate)
Change in temperature
Change in smell
Chemical Equations
Scientists use chemical equations to represent reactions in a short
and simple way.
Example:
Magnesium + Oxygen → Magnesium Oxide
Balanced equation:
2Mg + O₂ → 2MgO
A balanced equation has an equal number of atoms on both sides.
Types of Chemical Reactions
Combination Reaction
When two or more substances join together to form a single
product, it is called a combination reaction.
