Lesson 3.1: Water Properties *Refer to Chapter 8 in your Textbook

Lesson 3.1 Learning Targets: Explain how water molecules bond. Identify the various properties of water. Differentiate between acids and bases.

Basic Chemistry Atoms are the smallest component of an element The subatomic particles that make up atoms are: protons neutrons electrons

Basic Chemistry Molecules are formed when 2 or more atoms are joined by covalent bonds Example: H2O

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

Basic Chemistry Hydrogen bonding is an attraction between water molecules

Water Properties Cohesion 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)

Water Properties Adhesion is the property of water causing an attraction between water and a different substance (Example: water sticks to the window when it rains)

Water Properties Surface Tension is the property of water causing it to be elastic (Example: A bug can walk on water)

Water Properties 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)

Water Properties Boiling Point: Heat Capacity: Fresh water = 212oF/100oC Salt 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

Water Properties Freezing Point: Freezing: Fresh water = 32oF/0oC Salt water = 28oF/-2oC Freezing: Water expands upon freezing Ice floats because it’s less dense

Water Properties Density = 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