BIO 101 Water and PH
What are the characteristics that water has that are essential to all living things
1.) universal solvent 2.) cohesive and adhesive 3.) resists changes in temperatures 4.) resists changes of state to a gas 5.) becomes less dense when it freezes
What do ionic compounds do in water?
Ionic compounds dissociate into ions (ionize) in water because they attract water molecules
why is water a universal solvent?
Most substances have charges on them and therefore attract the positive or negative ends of the water molecules
Hydrogen Bond
The attraction between a partial charged hydrogen and another atom with a partially negative charge THEY ARE VERY WEAK. EASILY BROKEN
Polar Covalent bond
Uneven sharing of electrons
what are buffers?
a combination of chemicals that combine with hydrogen and hydroxide ions to help resist changes in ph
Polar Molecule
a molecule where one end is positive and the other end is negative
Definition of Water
a molecule where oxygen shares electrons with two hydrogens
why can water resist changes in temperature?Why is this important
hydrogen bonding between water molecules impedes them from accelerating their speed rapidly helps maintain temperature of all organisms cause the water temperature isnt changing
everytime ph increases by on unit
hydrogen ion decreases by 10
Why does it matter that water is a universal solvent?
it facilitates chemical reactions because it is easier for molecules to react if they dissolve in water
why is water adheisve
it is attracted to any substance that has a charge
acid
more hydrogen than hydroxide ions
basic of alkaline
more hydroxide than hydrogen
Universal Solvent
nearly all molecules dissolve in water ions, sugars, amino acids FATS AND OILS DO NOT
why is water Cohesive
one molecule is attracted to another because it is polar (COHESTIVE)
charges of H2O
oxygen gains 2 partial negative charges and hydrogen gains a partial positive charge
Water
oxygen is highly electronegative so the electrons are more strongly attached to the oxygen than the hydrogen Electrons are more often in oxygens orbit than in hydrogens orbit
pure water
same number of hydrogen and hydroxide ions
why is this signifigant(cohesive and adhesive water)
this helps blood travel through vessels called capillary action and is responisble for the movement of blood in a capillary tube
what is cohesive and adheisve mean
water is attracted to itself (COHESIVE) water is attracted to most other substances (ADHESIVE)
water becomes less dense when it freezes. how and why is this important
when water freezes it creates four relatively stationary bonds with other water molecules and the geometry forces other water molecules further apart bodies of water freeze from top down this helps fish
