Question

A ___________ is a substance made up of two or more elements.

Answer 1

• A compound is a substance made up of two or more elements chemically combined in a fixed proportion by mass.
• When one or more atoms of the same or different elements combine chemically, a compound is formed.
• Water (H₂O), for example, is a compound composed of two elements, hydrogen, and oxygen, chemically united in a constant proportion of $1:8$ by mass (Atomic masses: $$\begin{gathered} \mathrm{H}=1\mathrm{u},\mathrm{O}=16\mathrm{u}, \\ \mathrm{hence}{\mathrm{H}}_2:\mathrm{O}=2\mathrm{u}:16\mathrm{u}, \\ \mathrm{or}1:8 \end{gathered}$$).\

Hence, A compound is a substance made up of two or more elements.