Final answer:
The properties of compounds differ significantly from the properties of the elements they are composed of, with the example of water (H₂O) demonstrating this by contrasting the flammable nature of hydrogen and oxygen gases with the non-flammable nature of their combination in water.
Step-by-step explanation:
The properties of a compound are usually quite different from the properties of the elements that constitute it. Compounds are formed when two or more elements combine in a fixed, whole-number ratio, creating a substance with unique chemical and physical properties. The properties of a compound do not merely blend the properties of the elements it's comprised of; instead, the compound exhibits new properties that are often not predictable based on the properties of the elements alone.
An example that illustrates this is the compound water (H₂O), which is composed of the elements hydrogen (H₂), a highly flammable gas, and oxygen (O₂), a gas that supaports combustion. When combined to form water, these gases create a liquid that is not flammable and actually extinguishes fire. This example clearly shows how the characteristics of a compound differ significantly from those of the original elements.