Lesson 3.1:Water Properties

*Refer to Chapter 8 in your Textbook

Learning Goals:

1. I can explain how water molecules bond.2. I can identify the various properties of

water.3. I can differentiate between acids and

bases.

AtomAtoms are the smallest component of an elementThe subatomic particles that make up atoms are:

protonsneutronselectrons

MoleculeMolecules are formed when 2 or more

atoms are joined by covalent bondsExample: H2O

Polar Covalent Bonds occur when two elements share electrons, but they are not shared equally

Polar Covalent Bond:

Hydrogen BondingHydrogen bonding is an attraction

between water molecules

CohesionCohesion is the property of water

making it attracted to other water molecules via hydrogen bonding

(Example: water poors out of a glass in a continuous flow because the molecules are sticking together)

Adhesion• Adhesion is the property of water

causing an attraction between water and a different substance

(Example: water sticks to the window when it rains)

Surface Tension: • Surface Tension is the property of water

causing it to be elastic (Example: A bug can walk on water)

Capillary Action: • Capillary Action is the movement of water

through small spaces due to the forces from cohesion, adhesion, and surface tension (Example: Water travels from a plant’s roots to its leaves)

TemperatureBoiling Point:

Fresh water = 212oF/100oCSalt water = 216oF/102oC

Heat Capacity:Water has the ability to regulate

temperature (prevent major changes) It requires a large amount of energy

to increase the temperature of water

TemperatureFreezing Point:

Fresh water = 32oF/0oCSalt water = 28oF/-2oC

Freezing:Water expands upon freezingIce floats because it’s less dense

DensityDensity = mass / volume Density of water = 1 g/cm3

The heavier an object, the greater the volume for an object to float

Density and Marine Organisms

Acids & Bases• Acids:

• produces H+ ions

• Base: • produces OH- ions

pH Scale • Acids: Lower on the pH scale (0-6)

• Bases: Higher on the pH scale (8-14)• Freshwater pH = 7• Seawater pH = 8