BIOLOGIC CHEMISTRY

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BIOLOGIC CHEMISTRY

• Honors Biology
• Chapter 2 The Chemical Basis of Life

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• 2.1
• Matter anything that occupies space and has
  mass
• Element a substance that cannot be broken down
  to another substance by ordinary chemical means.
• Trace elements essential for humans in very
  small amounts

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BIOLOGIC CHEMISTRY

• 2.1
• Trace elements essential for humans in very
  small amounts
• 2.3
• Compound a substance containing two or more
  elements in a fixed ratio

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BIOLOGIC CHEMISTRY

• 2.4 ( more)
• NATURE OF MATTER
• ATOMS Basic unit of matter
• The smallest portion of a substance that still
  retains the unique properties of that substance.
• PROTONS positive charge
• NEUTRONS neutral or no charge
• ELECTRONS negative charge

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• NUCLEUS
• CENTER OF ATOM
• CONTAINS PROTONS AND NEUTRONS
• ORBITALS
• CONTAIN ELECTRONS
• In a neutral atom, the number of protons equals
  the number of electrons

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CHEMICAL ELEMENT Atomic Number protons
Atomic Mass protons neutrons ISOTOPES Var
y in number neutrons Same Chemical
Properties Some Radioactive
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• 2.6
• Electrons orbit a nucleus at different levels
  like the layers of an onion. The layers or
  orbits that are closer to the nucleus are lower
  in energy. Just as potential energy increases as
  you move up the steps of a ladder, energy levels
  increase as electrons fill the orbits moving away
  from the nucleus.

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• ELECTRON CONFIGURATION
• ENERGY LEVELS may CONTAIN
• 2, 8, 18 or 32 electrons

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• ELECTRON CONFIGURATION
• ENERGY LEVELS may CONTAIN
• 2, 8, 18 or 32 electrons
• Electrons in each level spend most of their time
  in areas called
• sublevels that have different shapes and hold
  different numbers of
• electrons
• ENERGY SUBLEVELS
• s level 2 electrons
• p level 6 electrons
• d level 10 electrons
• f level 14 electrons

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Periodic chart (including Bohr models)
BIOLOGIC CHEMISTRY

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Periodic means repeating in a pattern Periodic
Table of Elements - the arrangement of elements
according to repeating changes in properties
. -The boxes for the elements are arranged in
order of their atomic numbers. -Vertical columns
are groups or families. -Horizontal rows are
called periods.
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The electrons responsible for the chemical
properties of atoms are those in the outer energy
level. Valence electrons - The electrons in the
outer energy level. Core electrons -those in the
energy levels below.
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Some matter is found naturally as elements, but
most is in the form of compounds. Compounds form
when different elements combine. Compounds have
different properties than the elements of which
they are made.
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CHEMICAL COMPOUNDS Substances that are formed
by the combination of two or more different
elements in a fixed ratio. They are pure
substances. MOLECULE Smallest unit of compound
covalently bonded.
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A chemical formula uses the symbols for the
elements in the compound. Na Cl ? NaCl Some
formulas include subscripts to show ratios of
more than one atom. 2 H 1 O ? H20
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CHEMICAL FORMULA Shorthand expression describing
chemical composition SIMPLEST FORMULA
CaN2O6 (Empirical Formula) MOLECULAR
FORMULA Ca(NO3)2 STRUCTURAL FORMULA
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STRUCTURAL FORMULA
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2.7 - 2.10

• CHEMICAL BONDS
• Bond energy is the energy necessary to break a
  chemical bond.
• COVALENT BONDS
• holds molecule together by sharing electrons
• IONIC BONDS
• holds molecule together by transfer of electrons
• VAN DER WAALS FORCES
• temporary dipole attraction between molecules
• Results in higher boiling points
• HYDROGEN BONDS
• Attraction between molecules with partially
  positive and partially negative areas

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• Covalent bonds may be
• Polar covalent Polar molecule
• Nonpolar covalent Nonpolar molecule
• Bonding Review Powerpoint

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• Hydrogen bonds- partially positive charged Hend
  of a molecule is attracted to partially negative
  charged end of another molecule

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Hydrogen Bonding
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CHEMISTRY OF WATER ATOMIC STRUCTURE 10
Protons 10 Electrons Covalent Bond Polar
Structure
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2.11 2.12
PROPERTIES OF WATER 1. COHESION Attraction
between molecules of the same substance. 2.
ADHESION Attraction between different
substances. 3. HIGH SPECIFIC HEAT 1Cal./gm/oC 4
. HIGH HEAT OF VAPORIZATION Heat energy (586
cal.) required to change 1 gm. liquid water to
gas.
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Heat total amount of energy associated with the
movement of atoms in a body of matter Temperature
the average speed of the molecules in a body
of matter
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2.13 Solid water ice is less dense than liquid
water.
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2.14
SOLUTION Homogeneous (uniform) mixture of a
liquid. solvent- dissolving agent solute-
substance that is dissolved aqueous solution-
solution with water as solvent MIXTURE
Substance composed of two or more elements or
compounds that are together BUT are not
chemically combined. SUSPENSION Composed of
nonpolar molecules in water. Water acts to
exclude them.
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2.15
ACID / BASE / pH pH (pouvoir
hydrogene) Calculated from the spontaneous
ionization of water, i.e. 1X10-7 M Negative
logarithm of the H Each change in a pH unit
is a tenfold change in concentration
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ACIDS Any substance that dissociates in water
to increase the H concentration BASES Any
substance that dissociates to decrease the H
concentration.
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BUFFERS Substance that acts as reservoir for
H
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Carbon, Hydrogen, Oxygen, Nitrogen comprise
96 living matter
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2.17
Chemical reaction- a process leading to changes
in the composition of matter Reactants- starting
materials Products- resulting material