Properties of Water

Balloon Activity There is a Balloon at every sink. Have someone inflate it and tie it off. Turn the water on as a very thin stream. Rub the balloon on someone’s head and hold it near (but not touching) the thin stream of water. Look closely. What happens?

Water is Polar Oxygen has a partial (-) charge Hydrogen has a partial (+) charge Oxygen has a high attraction to Hydrogen’s valence electrons Causes water to be POLAR, like a magnet

Covalent Bond vs. Hydrogen Bond VIDEO Covalent Bond

How do water molecules bond to each other? Try bonding with your classmates.

Polarity of Solvents LIKE Dissolves LIKE Solvents dissolve LIKE substances For instance, POLAR solvents (like water) dissolve only POLAR or IONIC substances In addition, NON-POLAR substances (like acetone) dissolve only NON-POLAR substances. LIKE Dissolves LIKE Why do you think this Oil won’t dissolve in water?

Quick Write for 2 minutes: What did you observe? 1

Water is Less Dense as a Solid Water in a liquid state keeps rebonding and changing its shape Water in a solid states has a fixed shape (crystalline lattice) with space in between making it less dense VIDEO 1

Properties of Water High Heat of Vaporization Polarity Cohesion High Heat of Fusion Less Dense as a Solid Universal Solvent Disassociation Polarity Cohesion Surface Tension Adhesion Capillary Action High Specific Heat 1

Cohesion Water molecules attracted to each other creating surface tension 1

Adhesion Water molecules are attracted to other substances such as glass, soil, and plant tissues 1

Capillary Action Ability of water to “climb” up against gravity Results from Cohesion + Adhesion EX: Water moving up the roots to the top of the tree 1

Space Video

Water is Less Dense as a Solid Water in a liquid state keeps rebonding and changing its shape Water in a solid states has a fixed shape with space in between making it less dense 1

Quick Write – 2 minutes If ice were more dense than liquid water, how would this impact the survival of marine life?

Surface Tension The tightness across the surface of water caused by adhesion Makes the surface act like a solid 1

High Specific Heat Amount of heat (energy) required to raise the temperature of water by 1⁰ C Example: WATER = 75°F BEACH = 110°F 1

High Specific Heat When hydrogen bonds break they absorb a lot of (heat) energy, leaving the water molecules behind cooler.

Balloon Video

Universal Solvent Water is called the universal solvent because it dissolves more substances than any other liquid Water dissolves polar substances and ionic compounds due to its polarity. 1

Rate of Dissolving The rate of dissolving is how quickly a solute can be dissolved by water. The rate of dissolving can be increased by: Increasing the surface area of the solute (crushing) Agitating (or stirring) the mixture Increasing the temperature of the solvent