Which of the following examples is NOT considered a pure substance?
A. Fruit punch B. Carbon C. A water molecule
The Correct Answer and Explanation is :
The correct answer is A. Fruit punch.
Explanation:
A pure substance is defined as a material that has a constant composition and consistent properties throughout the sample. It can be an element or a compound. In contrast, mixtures, such as fruit punch, consist of two or more substances that are physically combined but not chemically bonded.
B. Carbon is an example of a pure substance, specifically an element. Carbon exists in several forms, including graphite and diamond, but all forms consist solely of carbon atoms, maintaining a uniform structure and composition. As an element, carbon cannot be broken down into simpler substances without losing its chemical properties.
C. A water molecule (H₂O) is also a pure substance, as it is a compound made up of hydrogen and oxygen atoms in a fixed ratio of 2:1. Water has distinct chemical properties, such as its boiling and freezing points, that do not change regardless of the sample size, thus maintaining its classification as a pure substance.
In contrast, fruit punch is a heterogeneous mixture made up of various ingredients, such as water, sugar, fruit juice, and artificial flavors. The composition of fruit punch can vary significantly depending on the recipe and preparation method, leading to different taste and properties. Moreover, in a mixture like fruit punch, the components can be separated by physical means, such as filtration or distillation, which is not possible with pure substances.
Understanding the distinction between pure substances and mixtures is essential in chemistry, as it affects how substances react, their physical properties, and their applications in various fields, from food science to pharmaceuticals. Thus, fruit punch, being a mixture, does not qualify as a pure substance.