The Greatest Solvent on Earth

BIOLOGY 392 Section 2-2 WATER! The greatest solvent on Earth I. Properties of Water  Phases: Solid, Liquid, Gas  Polarity  Hydrogen bonds o Adhesion o Cohesion  Making Mixtures o Solutions o Suspensions  Making Acids and Bases

A. Water Density 1. Ice is ______2. When water freezes ______frozen ice making the cube larger and less dense 3. Benefits: a. Fish and plant life can survive in liquid layers of water under ice

4. PHASE CHANGES: a. ______b. gas, liquid, solid

B. Polarity 1. Water is polar 2. the compound is ______a. Hydrogen becomes 

b. Oxygen becomes 

3. Hydrogen Bonding a. Due to polarity, ______

b. Slightly ______oxygen attracts slightly ______hydrogen from another i. COHESION

ii. ADHESION 

C. Mixtures 1. The greatest solvent on Earth! 2. Water’s polarity allows it to 

3. Definition  4. Types of Mixtures

a. SOLUTIONS 

i. Distributes evenly ii. “Like dissolves Like” iii. Ex: b. SUSPENSIONS 

i. Example:

RECAP 1. Why does ice float on a lake?

2. Explain the polarity of water – how are the charges distributed?

3. What is the difference between adhesion and cohesion?

4. Explain the difference between a solution and a suspension

D. Water Dissociation 1. Water can break apart on its own into 2 charged ions a.

II. ACIDS & BASES 1. Water can react to form individual ions: 2. In pure water this occurs naturally

3. H+ is always ______OH- so water remains ______

A. pH scale: “the power of Hydrogen”

1. Some solutions made with water become acidic or basic. 2. This is determined by ______3. pH = - log [H+] a. Example: [H+] = 1 x 10 -5 à pH = 5 (acid) = [H+] = 1 x 10 -9 à pH = 9 (base) = B. Acids 1 pH range ______2 Definition:______3 H+ ions ____ OH- ions 4 The closer ______the more acidic the solution 5 Examples: ______

C. Bases (Alkaline) 1. pH ranges ______2. Definition  ______3. OH- ions ______H+ ions 4. The closer ______the more basic the solution 5. Examples: ______

D. pH and Living Things 1. pH values in living cells ______a. Optimal pH for chemical reactions to take place in the body b. Any switch in pH could cause serious/fatal problems E. Buffers 1. Definition  ______2. Function  ______3. There are natural buffers in your blood that keep the pH ______

RECAP 1. What makes a solution acidic or basic?

2. How is acidity measured?

3. A solution with pH 8.5 is considered….