Final answer:
A single water molecule (H₂O) is composed of two hydrogen atoms bonded to one oxygen atom, while tap water is a mixture including various minerals and impurities. Water's polarity and hydrogen bonding contribute to its unique chemical properties. The presence of additional substances in tap water affects its properties and behavior, differentiating it from a pure water molecule.
Step-by-step explanation:
A water molecule, H₂O, is different from a mixture in a glass of tap water because it consists of a single oxygen atom bonded to two hydrogen atoms, creating a distinct molecular structure with polarity. Tap water, on the other hand, is a mixture that contains various dissolved minerals, gases, and even impurities in addition to water molecules. The interactions between molecules in tap water are more complex due to the presence of these additional substances, which can affect its chemical properties and behavior.
In a water molecule, the oxygen atom is more electronegative, causing the electrons to be drawn closer towards it, and leaving the hydrogen atoms with a slight positive charge. This molecular polarity results in hydrogen bonding, giving water its unique properties, such as a high boiling point and the ability of ice to float on liquid water because it is less dense. The structure of water molecules changes between states: in its liquid form, hydrogen bonds are continually being broken and formed, but in a solid state, water forms a crystalline structure, which is responsible for ice being less dense.
Tap water contains additional elements that can include minerals like calcium and magnesium, and even trace amounts of contaminants depending on its source and treatment process. These elements are not part of the water molecule's chemical structure, but they interact with and can alter the properties of the water they're mixed with.