Question

The substance that is composed of two or more elements, chemically combined with one another in a fixed proportion of mass is called ___

Answer 1

Compounds can be defined as substances consisting of two or more different types of elements in a fixed ratio of its atoms. When the elements combine, some of the individual property of the elements is lost and the newly formed compound has new properties.

For example- The chemical formula for common salt is $NaCl$ which shows one atom of sodium and one atom of chlorine combine to form one molecule of $NaCl$.