Water 6.3

Chemistry of Water http://www.nsf.gov/news/special_reports/chemistrynow/chem_water.jsp

Water is a polar molecule The hydrogen and oxygen atoms are covalently bonded.

Because O has a larger nucleus it keeps the electrons for a longer period of time. H gets the electrons for a shorter period of time. Therefore Oxygen tends to have a more negative charge and the hydrogen tend to have a more positive. A positive side and a negative side = a polar molecule

Hydrogen Bonds

Hydrogen Bonds are. . . A weak interaction involving a hydrogen atom and a fluorine, oxygen, or nitrogen atom. They give water a lot of its properties.

Cohesion vs. Adhesion Cohesion-attractive force between particles of the same kind. Example: Surface tension of water. Adhesion-attractive force between unlike substances. Together, cohesion and adhesion can make water move UP against the force of gravity. This is called capillary. Example water from a vase moving into a flower’s stem.

(a substance that another substance is dissolved) Solute Mixtures Homogenous (solution) Solvent (a substance that another substance is dissolved) Solute (the substance that is dissolved) Heterogeneous Colloids (particles do not settle out) Suspensions (particles eventually settle out)

The pH scale