lesson 3 Flashcards
atoms are composed of
protons
neutrons (except H)
electrons
atoms are the smallest, stable components of cells
element
atomic number
mass
weight
atomic mass
dalton
isotopes
atoms of the same element that have different numbers of neutrons
electrons determine an atoms chemical behavior
number and arrangement of electrons determine an atoms interaction
cation
more protons than electrons
(+) charge
anion
more elctrons than protons (-) charge
chemistry of life is based on water
water =70%
macro molecules=26%
small molecules=4%
water is essential for life: cohesion
the polartiy of water promotes the attraction of water molculess for other water molecules
indivual H bonds are weal and short lived
combined effect of many H bonds is substantial
cohesion means
water is a liquid at most temperatures on earth and creates surface tension
water is essential for life: adhesion
polarity of water promotes the attraction of water and other polar molecules
adhesion of water to charged surfaces
drives capillary action
water essential for life: high specific heat
reflects extent to which a substance resists changing temperature when it absorbs or loses heat
water essential: high heat of vaporization
heat of vaporization=amount of energy required to change 1 gram of substance from liquid to gas
reflects energy is needed to to break H bonds to allow conversion of gas
water is essential for life: solid water is less dense than liquid water
ponds and lakes
