The Aquatic Ecosystem — Chemical Properties of Water

About this lesson

This unit focuses on the chemical properties of water within the context of aquatic ecosystems. It explains the structure of a water molecule, including its covalent bonds and the 104.5° angle, and discusses water's polarity due to oxygen's higher electronegativity. The text describes hydrogen bonding between water molecules, which contributes to water's high boiling point compared to similar compounds like hydrogen sulfide. It also covers water as a universal solvent, using the dissociation of table salt (NaCl) as an example, and explains ionic equilibrium in pure water. Additionally, the unit introduces the hydrolysis of salts, categorizing salts as acidic, basic, or neutral based on their effect on H+ and OH- ion concentrations, and explains the pH scale, ranging from 0 to 14, with pure water at pH 7. A practical activity is included for measuring pH values of different water samples using a pH meter or test strips. By the end, students should understand water's molecular structure, its role as a solvent, the concepts of hydrolysis and pH, and be able to classify salt solutions as acidic, basic, or neutral.