Chemical Changes and Reactions — Question 9

(a) A reaction in which two or more substances combine together to form a single substance is called a synthesis or combination reaction.

A + B ⟶ AB

(b) Synthesis is a direct combination reaction.

In the above reaction, substances A and B combine to give a molecule of a new substance, AB (Product).

For example, carbon burns in oxygen to form a gaseous compound, carbon dioxide.

C + O₂ $\xrightarrow{\Delta}$ CO₂ ↑