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