International General Certificate of Secondary Education (IGCSE) Chemistry Practice Exam

How is a saturated compound characterized?

1. A molecule containing only single bonds

2. A molecule containing multiple bonds

3. A molecule with no carbon atoms

4. A molecule containing functional groups

The correct answer is: A molecule containing only single bonds

A saturated compound is characterized as a molecule containing only single bonds between carbon atoms. This means that all available bonding sites on the carbon atoms are filled with hydrogen atoms, leading to a structure that is fully "saturated" with hydrogen. In organic chemistry, saturation is important as it affects the physical and chemical properties of the compound. Saturated compounds typically include alkanes, which have the general formula CnH2n+2. While molecules with multiple bonds (such as alkenes and alkynes) are unsaturated because they can react and add more atoms (like hydrogen) to their structure, those with only single bonds are stable and do not have sites for additional bonds. Molecules with no carbon atoms or molecules solely defined by their functional groups do not fit the definition of saturated compounds, which must specifically contain carbon and hydrogen linked by single bonds.