1. 1

2. Draw the covalent dot diagram for water.
Think about it as we discuss the properties of water. 2

3. Electron pair geometry- tetrahedral Molecular geometry- Bent
2 bonded pairs of electrons
2 unbonded(lone) pairs of electrons
It is NOT linear
and sticklike H-O-H 3

4. Liquid at room temperature Colorless, odorless, tasteless
Physical Properties of water:
Liquid at room temperature
Colorless, odorless, tasteless
MP/FP = 0 Standard Pressure
BP = 100 Standard Pressure
Density = 1.00 g/cm3
Specific Heat = 4.18 J/g∙ °C

5. Two unique factors of water Water is POLAR COVALENT
Water- H2O
Two unique factors of water
Water is POLAR COVALENT
Share electrons unequally
Oxygen is more electronegative than hydrogen.
Electrons are more attracted to oxygen vs. hydrogen.
Oxygen is partially negative
Hydrogen is partially positive

6. Ionic solutions dissolved in water increase conductivity
Opposite charges attract, the oppositely charged parts of the molecule of the solute( what is being dissolved) and the solvent(water) attract to each other.
The molecules of the solute are pulled away from the solid and into solution.
Ionic solutions dissolved in water increase conductivity 6

7. 7

8. Water- H2O Water forms Hydrogen bonds
Hydrogen atoms in one water molecule form attractions to the oxygen atoms of other water molecules.
The strong INTERMOLECULAR FORCE between water molecules leads to the formation of hydrogen bonds.
Hydrogen bonding contributes to
the unique properties of water like
High surface tension
High specific heat
High adhesion
High cohesion
Density of solid ice

9. Water has a high specific heat
Resists changes in temperature which causes water to have a low freezing point and high melting point.
Energy is absorbed by bonds in and between water molecules.
Useful for cooling other systems because it absorbs energy with minimal changes to its temperature.
Helps regulate the temperature of living organisms

10. Water is neutral in pH
Dissociates into hydrogen (H+) ions and hydroxide (OH-) ions
Produces hydrogen (H+) ions and hydroxide (OH-) ions at the same ratio.

11. Density of solid water
In general, the particles in a solid are more closely packed than those in a liquid.
Thus, most solids are more dense than most liquids.
Water is the exception. Solid water is less dense than liquid water
Ice floats on bodies of water, insulating the water below. allowing aquatic life to survive winters, and preventing bodies of water from completing freezing.

12. The hydrogen and oxygen atoms align themselves into a crystal pattern that has more space between each molecules.
Close packed water molecules
Open crystal lattice of ice

13. Cohesion Adhesion Attraction between molecules of the same substance.
Drops of water form on substances, such as table tops, because water molecules are draw inward due to cohesion
Adhesion
Attraction between molecules of a difference substance
Leads to water traveling from a plants roots to its stems and leaves.

14. Surface water molecules are H bonded only on the inside of the drop.
Surface tension
Surface tension is a measure of the inward pull by particles in the interior of the liquid.
Surface water molecules are H bonded only on the inside of the drop.
Click box to view movie clip.

15. Surface tension
The stronger the attractions between particles, the greater the surface tension.
Soaps and detergents decrease the surface tension of water by disrupting the hydrogen bonds between water molecules. When the bonds are broken, the water spreads out.
Compounds that lower the surface tension of water are called surfactants.

16. Forces between molecules or particles

17. Generally, intermolecular forces are much weaker than intramolecular forces.

18. Hydrogen bonding is a significant intermolecular force.
Hydrogen must be bonded directly to a very electronegative atom such as nitrogen, oxygen, or fluorine

19. 1. Ammonia(NH3) and water have similar structures, but the forces between the molecules of ammonia are weaker. How would the properties of ammonia differ from those of water?
A. Ammonia would have a lower heat capacity.
B. Ammonia would have a greater molecular weight.
C. Ammonia would have a higher boiling point.
D. Ammonia would be more cohesive.

20. Which of the following describes cohesion in action?
A. the ability of a liquid to dissolve substances.
B. The force needed to break through the surface of a liquid.
C. The density of a liquid in a long tube.
D. The rise of a liquid in a narrow tube.

21. Which aspect of water makes it an excellent solvent?
A. It has a high heat capacity.
B. It has a low freezing point.
C. Its crystal form is less dense than its liquid form.
D. It is polar and forms hydrogen bonds.