Download • Covalently bonded • Carbon compounds • Almost always contain

Chapter 4.4: Organic and
Biochemical Compounds
Organic Compounds
• Covalently bonded
• Carbon compounds
• Almost always contain
hydrogen
Organic molecules contain carbon,
usually hydrogen,
Aspirin contains acetylsalicylic acid,
C9H8O4
And assorted other atoms
may be included, like
Oxygen, nitrogen, sulfur
and phosphorus
(notice all are nonmetals, so they form covalent bonds)
Carbon has four valence electrons
• So it will make four bonds with other
atoms willing to share their electrons.
• Including other carbon atoms!
Naming rules
Number of carbons
• Meth- 1
• Eth2
• Prop- 3
• But4
• Pent- 5
• Hex6
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Alkanes
Naming for different types of bonds
• -ane
only carbon-carbon single bonds
• Only single covalent bonds.
• -ene
contains a carbon-carbon double
bond
• Methane, CH4
• -yne
contains a carbon-carbon triple
bond
Another way to look at methane
• “Single bond” means that the carbon is
sharing only one electron with each of the
four hydrogen atoms.
Propane
• The “prop-” means three carbons
• And the “-ane” means all single bonds
Ethane, C2H6
Alkanes:
Single carbon-carbon bonds
• The two carbon atoms are only sharing one pair of
electrons, one from each of the two carbon atoms.
Alkenes
• Double bonds (two carbons are sharing two
pairs – four atoms)
2
Propene and Butene
•
propyne
ethyne = triple bond
• Two carbons sharing
3 pairs (6 electrons)
Alcohols have an –OH group
• One of the hydrogens is replaced by an –
OH group. Since there are two carbons,
this is ethanol.
Polymers
• Big molecules made
of repeating units.
• The units are
attached to one
another by bonds, like
beads strung together
on a necklace.
Polyethene
• Poly means “many”
• So it’s a large
molecule made up of
a series of “ethenes”
(C2H4)
• Plastic in soda
bottles, etc. made of
long noodle-like
chains of these units.
• Each unit = monomer
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Polymerization
• Free Radical Propagation
• click here to see how polymers are formed
from individual ethene molecules
Elasticity
• Cross-linked (like
chain link fences or
tennis nets) are
flexible, but snap
back into shape.
• Molecules in a rubber
band are examples.
Starch
Shape of polymer determines
properties.
• Polyethene isn’t elastic, so when you
crush bottle it doesn’t “bounce” back.
• This is because the long noodlelike chains
can be bent easily, but they slide and slip
instead of springing back into shape.
Carbohydrates
• Glucose is a
carbohydrate.
Large polymers of sugars
are carbohydrates,
often called “starch”.
Carbohydrates can be
100's of sugars long.
Body breaks the larger molecules
into smaller glucose “units” again
during digestion.
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Proteins
• Made up of repeating units called
• amino acids.
•CHON and
sometimes S!
DNA
• Adenine and
• Thymine
• Cytosine and
• Guanine
• CHONP
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