Unique  Properties Of  Water  New
Upcoming SlideShare
Loading in...5
×
 

Unique Properties Of Water New

on

  • 3,008 views

 

Statistics

Views

Total Views
3,008
Views on SlideShare
3,007
Embed Views
1

Actions

Likes
0
Downloads
55
Comments
0

1 Embed 1

http://www.slideshare.net 1

Accessibility

Categories

Upload Details

Uploaded via as Microsoft PowerPoint

Usage Rights

© All Rights Reserved

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Processing…
Post Comment
Edit your comment

Unique  Properties Of  Water  New Unique Properties Of Water New Presentation Transcript

  •  
    • Used almost universally for purification, cleansing & blessing
    • The life and climate of Earth as we know it would not exist without the unique properties of water.
    • The unique properties of water are based on the chemical makeup of the water molecule.
    • In order to understand, these unique properties and the makeup of a water molecule, let’s explore a little basic chemistry.
    • An atom is:
    • The smallest unit of a pure substance (element) which cannot be broken down by ordinary chemical means
    • Composed of protons, neutrons and electrons
    • Elemental units of which everything is made
    • Atomic Diameters: one to a few hundred millionths of an inch
    • Atoms bonded together
    • Bonds:
    • forces that hold atoms together
    • form when atoms with correct fit collide with sufficient force
    • store energy
    • Covalent bond: atoms collide and electrons rearrange so that some of the electrons are shared by the two atoms
    • Polar covalent bond: unequal sharing of electrons
    • Attraction between a hydrogen atom and an atom such as oxygen or nitrogen that is either part of another molecule or located at a distant site on the same molecule.
    • Both the hydrogen atom and the other atom must be involved in a polar covalent bond
    • This causes water molecules to “stick together”
    • Specific heat: the amount of heat required to raise or lower the temperature of 1 gram of substance 1 degree C.
      • A lot of heat energy is required to break hydrogen bonds, therefore water resists temperature change.
      • When water is heated, most of the heat is used to break hydrogen bonds and not much is left over to raise the temperature of the water.
      • In other words, water can absorb a lot of heat with little change in temperature.
      • Because of this water acts as a thermal buffer.
    • Because water acts as a thermal buffer (aka has high thermal capacity),
      • Water in the ocean resists temperature change by heating and cooling more slowly
      • This results in a lower range of temperature in the ocean temperatures than in the atmosphere
        • Ocean temperatures vary by no more than 2°C (3.5°F)
      • This creates a hospitable environment for life.
        • Especially in coastal areas which experience warmer winters and cooler summers due to proximity to ocean.
      • Water is described as having a high thermal capacity
    • It requires energy to change states
      • Melting
        • Solid to liquid  Heat of fusion
      • Evaporation
        • Liquid to gas  Heat of vaporization
      • Condensation
        • Gas to liquid  Heat of condensation
      • Freezing
        • Liquid to solid  Heat of fusion
      • Sublimation
        • Solid to gas  Heat of sublimation
    • Heat of vaporization: The amount of heat required for 1 gram of a substance to be converted from a liquid to a gas.
      • Hydrogen bonds make it difficult for water molecules to escape the liquid state and are responsible for water's high heat of vaporization.
      • The hydrogen bonds must be broken before water can evaporate and this requires considerable energy.
    • Because water has a high heat of vaporization:
      • It helps our bodies and our planet to maintain our temperature within a tolerable range.
      • When we get hot and sweat, water evaporates from our skin and cools us. Since the evaporation of water requires a considerable amount of energy, it is very effective in cooling us.
      • Water helps moderate global climate by absorbing solar radiation and dissipating the heat by evaporation of surface water.
    • Most substances increase in density as temperature decreases because the molecules making up the substance begin to move more slowly and get closer together.
    • Water is unique in the way temperature affects its density.
      • The density of water increases as it is cooled to 4 degrees C
      • and then its density begins to decrease as the temperature decreases to 0 degrees C, the freezing point of water.
      • As the freezing point is approached, hydrogen bonds relax and form a crystal lattice that keeps molecules further apart than they are in liquid water.
      • This is the reason why ice floats and ponds don't freeze solid.