Ch 3-Water Flashcards Preview

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Flashcards in Ch 3-Water Deck (5)
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1

Prroperties of water that are critical to maintaining life

  • Cohesive behavior
  • Ability to moderate temperature
  • Expansion upon freezing
  • Versatility as a solvent

2

Why water is an excellent solvent

It is such a good solvent because its polarity allows it to dissolve both ionic bonds and other polar molecules.

3

Waters Cohesive & Adhesive Properties

  • Cohesion
    • The tendency for like molecules to stick together
    • Caused by hydrogen bonding
  • Adhesion
    • The tendency of two kinds of molecules to stick together

4

PH scale

  • In any aqueous solution at 25°C, the prodduct of H+ and OHis constant and can be written as [H+][OH-] = 10-14
  • The pH of a solution is defined by the negative logarithm of H+ concentration, written as pH = -log [H+]
  • For a neutral aqueous solution, [H+]is 10-7, so pH = -(-7) = 7

5

Acids, Bases, & Buffers

  • Acids
    • a chemical substance that neutalizes alkalis, dissolves some metals, and turns litmus red; typically, a corrosive or sour-tasting liquid of this kind
  • Bases
    • Either of the nucleotide bases linked by a hydrogen bond on opposite strands of DNA or double-stranded RNA
  • Buffer
    •  A solution that resists a change in pH when acids or bases are added