Transcript Chemistry = Evil - Whitehall District Schools

Chemistry = Evil
A playful frolic through the very core
of your being…….
Chapter 2
The Nature of Matter
 Atom:
Basic unit of Matter
 Made up of:
–Proton (+), in nucleus
–Neutron (Nuetral), in nucleus
–Electron (-), in energy levels
The Nature of Matter
 Element:
pure substance that
consists entirely of one type of
atom. (Na, C)
 Compound: substance formed
by the chemical combination of
two or more elements
Chemical Bonds
 Hold
atoms together in compounds
 Where the Energy (E) is stored and
released
 Two main types of bonds
–Ionic
–Covalent
Ionic Bonds
 The
chemical bond in which
electrons (e-) are transferred from
one atom to another
 Loss or gain of these electrons
forms ions
 Example: NaCl (Ionic Bond Movie)
Chlorine atom (Cl)
Sodium atom (Na)
Chloride ion (Cl-)
Sodium ion (Na+)
Covalent Bonds
 The
chemical bond in which
electrons are shared
 e- are located between atoms
 These are the strongest bonds
 Covalent Bonds
Water
 Life
on earth evolved from
H2O
 Living Cells are 70-95%
H2O
 Covers 3/4 of the earth
 Exists in all states in
nature.
 Moderates T on Earth
Hydrogen bonds in
Water
H2O’s Polarity and
Effects
 Water
is polar because of
uneven distribution of
electrons between H and O
 The polarity results in
Hydrogen bonding
 This orders H2O into higher
structural organization
 Organisms depend on cohesion
of H2O molecules

Cohesion: A substrate
being held together by
hydrogen bonds
 Adhesion: the attraction
btwn Molecules of
different substances,
causes surface tension

Surface Tension:
Measure of how difficult
it is to stretch or break
the surface of a liquid.
This causes water to
bend!
Water’s Specific Heat
 SH:
amount of heat
absorbed or lost for
one gram of
substance to change T
by 1 0 C
 H2O High specific
0
heat, (1 cal/g/ C)
Carbon

Organic Chemistry:
study of compounds
that contain carbon
atoms
 Why is carbon
Important?
Carbon

Important:
–Can bond with many
elements
–4 valence e-, so can make
4 strong covalent bonds
–Makes long, stable
chains, foundation for
life
Macromolecules
 Formed
by polymerization
–Monomers to polymers
 Form:
–Carbohydrates (Energy)
–Lipids (Store E, Membranes)
–Nucleic Acids (Nucleotides)
–Proteins (AA’s, build everything)
 On
a sheet of paper, make a list of at
least ten things that contain carbon.
 2. Working with a partner, review your
list. If you think some things on your
list contain only carbon, write “only
carbon” next to them.
 3. If you know other elements that are
in any items on your list, write those
elements next to them.
Concept Map
Section 2-3
Carbon
Compounds
include
Carbohydrates
Lipids
Nucleic acids
Proteins
that consist of
that consist of
that consist of
that consist of
Sugars and
starches
Fats and oils
Nucleotides
Amino Acids
which contain
which contain
Carbon,
hydrogen,
oxygen
Go to
Section:
Carbon,
hydrogen,
oxygen
which contain
which contain
Carbon,hydrogen,
oxygen, nitrogen,
phosphorus
Carbon,
hydrogen,oxygen,
nitrogen,
Chemical Reactions
 Process
that changes one set of
chemicals into another set
 Involve the breaking of bonds
in the reactants and the
formation of new bonds in the
products
E in Reactions
 Chem
Rxns that release energy
(Exothermic) often occur
spontaneously
 Chem Rxns that absorb energy
(Endothermic) will not occur
without a source of energy
E in Reactions Con’t
 Activation
E: the energy
needed to start a reaction
Energy-Absorbing Reaction
Energy-Releasing Reaction
Activation energy
Activation energy
Enzymes
 Proteins
that act as biological
catalysts
 Catalysts: a substance that speeds
rate of chemical rxn
 Cells use enzymes as catalysts for
rxns too costly for living tissue
Reaction pathway
without enzyme
Activation energy without
enzyme
Activation energy
Reaction
pathway with
enzyme
with enzyme
Enzymes con’t
 Are
substrate specific (figure 2-22,
pg 53)
 Substrate: reactants of enzyme
catalyzed rxns
 Enzyme action controlled by T,
pH, and hormones