Chapter 15: Water Chemistry & Solutions

A. Water, Water, Water! Water Facts: About 75% of the Earth’s surface is covered in water About 97% of all water is salt water (not fit for consumption) Of the remaining 3% that is freshwater, less than 1% is available for human consumption Most in frozen glaciers and ice caps Human body is more than 60% water Blood is 92% water Brain and muscles are 75% water Bones are about 22% water

B. Water Properties Water is a covalent molecule Composed of two nonmetals (hydrogen and oxygen) SHARING electrons Water is a polar molecule Hydrogen and oxygen do not share electrons equally Leads to partial positive and partial negative charges

C. Water’s Polar Nature Hydrogen Bond – weak bond between two molecules resulting from an electrostatic attraction between a highly electronegative atom (usually nitrogen, oxygen, or fluorine) Hydrogen bonds explain why water behaves the way it does!

D. Water Properties Cohesion – attraction of molecules to one another Causes water to form drops (beads)

D. Water Properties Adhesion – attraction that causes two different substances to join

D. Water Properties Surface Tension – occurs as a result of like molecules banding together to form a somewhat impenetrable surface (due to cohesion) Fails

D. Water Properties Capillary Action – ability of a liquid to flow in narrow spaces against the force of gravity Due to adhesive and cohesive forces