chp. 2 Flashcards
Pattern component: small molecules, complex carbon containing substances exist and are required for life
Process component: early in earth’s history simple chemical compounds combined to form more complex carbon containing substances before the evolution of life
chemical evolution hypothesis
atoms are most stable when their valence shells are
filled
valence shells can be filled through
chemical bonds
chemical composition of life
O>N>C=H
A strong attraction where two atoms share one or more pairs of electrons is called a
covalent bond
Attractive forces overcoming repelling forces cause
covalent bonds
ex: Hydrogen combining with Hydrogen to form H-H.
the water molecules surrounding nonpolar molecules form hydrogen bonds with one another and increase the stability of these interactions.
hydrophobic interactions
electrons are shared equally or symmetrically C-H.
Polar covalent bond: asymmetric sharing of electrons. H2O
non polar covalent bond
similar to covalent, but instead of being shared between two atoms, the electrons in ionic bonds are completely transferred from one atom to the other. Na+
Hydrogen bond: when two water molecules approach each other, the partial positive charge on hydrogen attracts the partial negative charge on oxygen. This is a weak electrical attraction between the molecules.
ionic bonds
Both OH bonds in water are
polar owing to the differences in electronegativity of H and O.
properties of water (5)
surface tension, small size, highly polar covalent bonds, specific heat, and can act as an acid and a base
acts as a base-tends to attract a proton
amino
acts as an acid-tends to lose a proton in solution
carboxyl
aldehydes especially react with certain compounds to produce larger molecules
carbonyl
highly polar so makes compounds more soluble through hydrogen bonding with water; may also act as a weak acid and drop a proton
hydroxyl
