PROPERTIES OF WATER

Structure of Water Shape 105 o angle Polar molecule – negative and positive pole

Hydrogen Bonding Hydrogen Bonds –Occurs with polar molecules –Between hydrogen and an electronegative atom in a nearby molecule (in this case: water)

Surface Tension Cohesion: another name for attractive forces of molecules to each other –each molecule of water is attracted in all directions (perhaps as many as four other water molecules) through hydrogen bonding –there is an inward force or pull which minimizes the surface area of any liquid. This causes surface tension

Surface Tension Adhesion: ability of water molecules to be attracted to solid surfaces

Meniscus is a curve in the surface of a liquid and is produced in response to the surface of the container or another object. Surface Tension acts on concave menisci to pull the liquid up

Capillary Action Adhesion of water molecules to the sides of a glass capillary tube pulls the water molecules up the sides of the tube. The cohesion of the water molecules to each other, pulls the rest along

Hydrate Compounds formed by the union of water with some other substance –Typically crystallized salts Example: CuSO 4 · 5H 2 O

Anhydrous A substance that is not in contact with water –Water has been removed When the water from MgSO 4 ·7H 2 O is driven off it becomes MgSO 4, an anhydrous compound.

Viscosity property of a fluid that offers resistance to flow Something that is viscous has a cohesive (molecules attracted to each other) and sticky fluid consistency Example: oil

Surface Tension/Surfactant Demo