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Chapter 2

BIO-0013 Chapter Notes - Chapter 2: Ionic Bonding, Chemical Evolution, Heat Capacity

Course Code
Susan Koegel

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Chapter 2.1: Atoms, Ions, Molecules
Chemical evolution:
pattern- in addition to small molecules, complex carbon-containing substances
exist and are required for life
Process- simple chemical compounds combined to form more complex carbon-
containing substances
Four types of atoms make up 96% matter- H, C, N, O
Covalent bonding: strong attraction in which 2 atoms share 1 or more e-
non polar + polar bonding
Electronegativity: some atoms hold electrons in covalent bonds more
Affected by:
#protons in nucleus
distance between nucleus and valence shell
Ionic bonding: electrons completely transferred not shared
Ions: cations +, anions -
Electron sharing continuum:
equal sharing transfer of e-
Nonpolar covalent Polar covalent Ionic
Chapter 2.2: Properties of Water + Early Oceans
Water is a solvent- agent for dissolving/getting substances into solution
Substances more likely to react when solutes have direct contact
Formation of Earth’s first oceanchemical evolution
Hydrogen bond: attraction between partial charges
H2O+polar molecules
Hydrophobic: substances that do not interact with water- nonpolar
Hydrophobic interactions: nonpolar molecules caged together by surrounding
Adhesion: partial + on H2O… partial - on glassupward pull
Cohesion: H2O… H2Onet pull lateral + downward
Surface tension: attraction between molecules at surface
Forms elastic membrane at surface
Liquid denser than solid
Ice- 4 H bonds, crystal lattice
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Liquid- bonds formed/broken, no lattice
High specific heat
Strong H bonds are hard to break
Molecules formed in ocean protected from energy
Chemical evolution
Acids: donate protons during chemical reactions + raise H3O concentration
HCl + H2OH2O+ + Cl-
Bases: accept protons during chemical reactions + lower H3O concentration
NaOHNa+ + OH-
Buffers: compounds that minimize changes in pH
reduce impact of adding acids/bases on overall pH
Chapter 2.5: Organic Molecules Importance
Organic compounds:
molecules that contain
carbon bonded to other
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