Chapter 2.2 Water Flashcards
2 characteristics of water
polar and hydrogen bonds from between them
What do Hydrogen bonding and bipolarity explain?
the cohesive, adhesive, thermal and solvent properties of water
Bonds between oxygen atom and 2 hydrogen atoms
polar covalent bonds
covalent bond
form when 2 atoms share electrons
Polar covalent bonding results from what
an unequal sharing of electrons
Why is water a polar molecule
it has different charges at each end and so exhibits dipolarity ( oxygen side somewhat negative and hydrogen sides somewhat positive)
Cohesion
molecules of the same type are attracted to each other
Ephemeral hydrogen bonding explains what events
- why water forms into droplets when it is split
- why water has a surface tension that allows some organisms to “walk on water”
- how water is able to move as a water “column” in the vascular tissues of plants
Adhesion
any attraction between two unlike molecules
Example of adhesion
when water molecules are attracted to cellulose molecules by hydrogen bonding, the attraction is adhesion because the hydrogen bonding is between two different kinds of molecules —> column of water in plant vascular tissue, cohesion and adhesion are both at work because the water molecules exhibit cohesion to each other but also adhesion to the inside of the vascular tubes.
Thermal properties of water
High specific heat: water can absorb or give off a great deal of heat without changing the temperature very much.
High heat of vaporization: water absorbs a great deal of heat when it evaporates. (perspiration)
Solvent properties of water
Excellent solvent of other polar molecules. The vast majority of molecules found inside and outside cells are polar. This included carbohydrates, proteins and nucleic acids. Most types of lipids are relatively non-polar. Water is also the medium in which most of the biochemistry of a cell occurs,
