Water Properties Lab. Water is Polar Covalent Hydrogen Bonds Weak bonds between like molecules.
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Water Properties Lab
Water is Polar Covalent
Hydrogen Bonds
• Weak bonds between like molecules
Cohesion
• Attraction of water to water
What forms a drop?
• Cohesion causes water to form drops
• surface tension causes them to be nearly spherical
• adhesion keeps the drops in place.
Surface Tension
• Water attracts itself and pulls in to form a “film” on its surface to form a drop.
Adhesion
• Attraction of water to an unlike substance• (like glass)• Note the drop is flatter than on wax paper
Water Drop Shapes
• Water cohesion to itself and forms a nice, round drop.
• Round drop on wax paper (not strong adhesion to water).
• As adhesion to glass is stronger + pulls the water, it makes a flatter drop.
On wax paper On glass
• More Cohesive More Adhesive
Water on wax paper
• Plain wax paper Soapy wax paper
You can break surface tension with soap.
Polar coheres to Polar not Nonpolar
• Water (Polar) has no adhesion to the wax (nonpolar) paper. It would roll right off.
• Water has more adhesion to a glass plate.
Climbing Property of Water• Colors are
separated by densities. Less dense colors go to the top.
• Black is composed of all the colors.
Capillarity – water climbs up small spaces
• The small spaces (pores of the paper) provide adhesion to the water.
• The water makes a column by cohesion to itself.
Adhesion to paperCohesion of water to water
Oil is hydrophobic
• Oil and water do not mix.
Oil is on top
Water is on bottom
Food coloring dissolves in water.
• Water is polar.• Food coloring is polar.• Oil is nonpolar (no charge).• Oil has no hydrogen bonding.
• Polar molecules dissolve
polar molecules.
Stirring oil and water
• The oil will go back to being separate from the water.
Oil sheen on water (oil on top of water in a thin layer)
Getting rid of oil on water• Detergent
breaks up the oil into very small droplets.
HowStuffWorks "How do you clean up an oil spill?“ (pick a video)
Booms
Burn Off
Hi-pressure water
Slick Sack
• Absorbent
padHand washing
Oil Spills Problems
• dead sea life
• human life
• cost of clean-
• up
Amphipathic
• molecules have (hydrophobic) and to attract oil structure, but also have a region that is polar (hydrophilic) attracts water to wash it away.
Like detergent.
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