Question

1. Fill in the blanks :
(a) A reaction in which two or more
substances combine to form a single
substance is called a .................... reaction.
(6) A
A .... .......... is a substance which
changes the rate of a chemical reaction
without undergoing a chemical change.​

Answer 1

$\huge\bf{Answer :}$

1. A reaction in which two or more substances combine to form a single substance is called a combination reaction.

2. A catalyst is a substance that changes the rate of a chemical reaction without undergoing a chemical change.

$\huge\bf{Extra\:Information :}$

Chemical reaction: It is a process in which one or more reactants react to form a new product is called a chemical reaction.

• A chemical reaction is represented by a chemical equation.

• The reacting substances (molecules, atom, and ion) which take part in the chemical reaction are called reactants.

• The new substances which are created as a result of the chemical reaction are called products.

Types of Chemical reactions:

1. Combination reaction
2. Decomposition reaction
3. Displacement reaction
4. Redox reaction (Oxidation and reduction reactions)
5. Exothermic and Endothermic Reactions.

There are some important characteristics of chemical reactions. They are :

• Evolution of a gas.
• Change in color.
• Change in the state.
• Change in temperature.
• Formation of a precipitate.