Water
Dihyrogen Monoxide
Physical Properties of Water
Without water, life would not exist
Structure of Water
Most of the physical properties of water are due to the structure of the water molecule
Formula: H2O
Two H atoms bond to one O atom at a 105° angle
Polar-covalent bond
The hydrogen and oxygen molecules form a covalent bond by sharing electrons
Due to this sharing of electrons, the water molecule is said to be polar
Polar: electrons are distributed unevenly across the molecule
Partial Charges
The oxygen carries a partial negative charge (δ-)
The hydrogen side of the molecule carries a partial positive charge (δ+)
The partial charges create the “poles” of the molecule
Attraction of water
molecules
The polarity of the molecule is what causes water to be attracted to other water molecules
Forms weak hydrogen bonds between molecules
Surface Tension and Cohesion
Due to water bonding to other water molecules, water has:
Activity 1 and 2
Cohesion and Adhesion
Activity 2:
What did you observe when dropping water onto the wax paper?
What did you observe when dropping water onto the glass?
Universal Solvent
Due to its polarity, water is able to dissolve a vast amount of chemical compounds
Depending on the interaction with water, substances are grouped as being either:
Demonstration 3 and 4
Hydrophilic vs Hydrophobic
Demonstration 3 and 4:
Is the table salt hydrophilic or hydrophobic? How did you know?
Is the oil hydrophilic or hydrophobic? How did you know?
Capillary Action
Capillarity (or capillary action) is the tendency of a liquid in a capillary tube or absorbent material to rise or fall as a result of surface tension
Water appears to defy gravity!
*How plants move water through their vascular systems
Activity 5
Solid, liquid, and gas...oh my!
Activity 6
What is unique about water in its solid form?
**Water is the only substance on Earth to occur naturally in all 3 phases of matter**