Final answer:
Table sugar, or sucrose, is a pure substance with a specific and constant composition of carbon, hydrogen, and oxygen. Despite different sources, sucrose's physical properties are consistent making it a pure molecular compound. It's used for its sweetening properties and should not be confused with artificial sweeteners like aspartame.
Step-by-step explanation:
Indeed, table sugar is considered a pure substance. This is because table sugar, or sucrose (C₁₂H₂₂O₁₁), has a specific and constant composition. Whether it is derived from sugar cane or sugar beets, the percentage of carbon, hydrogen, and oxygen by mass in sucrose remains unchanged at 42.1%, 6.5%, and 51.4% respectively. As a pure substance, sucrose exhibits consistent physical properties such as melting point, color, and a distinctive sweetness.
Sucrose is a molecular compound composed of individual sugar molecules that are held together by intermolecular attractive forces. When it dissolves in water, the intermolecular forces are disturbed, but the covalent bonds within the molecules remain intact. The dissolving process leads to sucrose molecules being separated and surrounded by water molecules, a process known as hydration.
As a molecular compound, sucrose is different from mixtures, which have variable compositions and might be homogeneous or heterogeneous. While sucrose is a pure organic compound, it's essential to note that not all sweeteners are pure substances. For example, aspartame is an artificial sweetener that is much sweeter than sucrose and is a methyl ester of two amino acids.