Properties of Water

Water Facts: Formula = H2O Three phases – Solid, liquid, and gas Freezing point = 0˚C Boiling point = 100˚C Inorganic molecule (aka: non-living, does not contain Carbon) Polar molecule Universal solvent About 70% of human body is water

Polarity Polar molecules: slightly positive at one end and slightly negative on the other end Water is a polar molecule!!!!!! Draw a picture definition of polarity on your note sheet in the empty box.

Polar molecules dissolve in water Non-polar molecules: No charge Polar molecules dissolve in water Non-polar molecules do not dissolve in water “Like” dissolves “like”

Universal Solvent Solvent – substance that does the dissolving Solute – substance dissolved in a solution Solution – mixture of solvent and solute http://programs.northlandcollege.edu/biology/Biology1111/animations/dissolve.html

Magic Sand Demo

What lab displayed Polarity?

Cohesion Attraction between substances of the same kind Ex: Water forming drops/beading Caused by hydrogen bonds between water molecules

Surface tension Prevents the surface of water from stretching or breaking easily Molecules at the surface of water are linked by hydrogen bonds Result of cohesion

Natures use of Surface Tension

Drops on a penny Demo

Adhesion Attraction between different polar substances Ex: things getting wet

Capillary Action Property in which water can travel up tubes Powered by adhesion Ex: plants, trees Attraction between walls and water is greater than effect of gravity

Celery Stalk Demo

What lab displayed both adhesion and cohesion?

Density Ratio of the mass of an object to its volume Density = Mass (g)___ Volume (ml) The density of water = 1.0 Density less than 1.0 = floats Density greater than 1.0 = sinks Ice floats, yet cold water sinks in ice, molecules spread out (ex: soda can in freezer) Cold water moves slower than warm water, causing it to sink

Soda Can Demo

What lab displayed density?

What causes water to do the amazing things it does? Polarity