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Carbon Chemistry and Polymers. What is so unique about Carbon?. Contains 4 valence electrons Can form single , double , or triple bonds Can bond with itself and many other elements. METHANE. Carbon has 4 valence Electrons. Carbon-Carbon Bonding. Types of Covalent Bonds. - PowerPoint PPT Presentation
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Carbon Chemistry and Polymers
What is so unique about Carbon?
• Contains 4 valence electrons
• Can form single, double, or triple bonds
• Can bond with itself and many other elements
METHANE
Carbon has 4 valence Electrons
Carbon-Carbon Bonding
Types of Covalent Bonds
Long Chain of Carbon Monomers
Carbon Nanotubes
An example of Carbon-Carbon Bonding
Organic Compounds
• Contain carbon and hydrogen
• Often combine with O,N,P and S
• Millions of organic molecules, make up more than 90% of all known compounds
• Covalently bonded: C – C or C – H are the most common types of bonds
History of Organic Chemistry
• Until 1828, thought that there were only 2 types of molecules: Made by living organisms or man made
• Organic compounds were thought to be only made by living organisms
• Friedrich Wohler mixed Silver Cyanate with Ammonium Chloride to produce Ammonium Cynate
• Made UREA instead:
• AgOCN + NH4Cl (NH2)2CO + AgCl
Carbon can combine directly with itself as a pure element in three
different forms
DIAMOND
GRAPHITE
FULLERENE
Diamond, Graphite and Fullerenes
Diamond
• Hardest mineral• Forms deep within the
earth under very high pressure
• Hard, rigid , strong and unreactive
• Cutting is very hard need to break many covalent bonds
Graphite
• Extremely soft and slippery
• The “lead” in pencils( mixed with clay)
• Carbon is bonded tightly in flat layers
• WEAK bonds so layers SLIDE easily
Fullerene
• Discovered in 1985 in soot of burnt Carbon Compounds
• Has only 60 carbon atoms!!!
• Large hollow sphere or cage of carbon
• A use for fullerenes may be to carry substances like medicines inside of them
HYDROCARBONS
• Molecules made up Carbon and Hydrogen
• Simplest hydrocarbon is Methane CH4
• Made by the decomposition of living matter• Often found in swamps and marshes
•
Where do hydrocarbons come from?
• Primarily from coal and petroleum • Formed 290 to 354 million years ago from
decayed plant and animal material
Alkanes: saturated hydrocarbonsAll have single bonds
Formula = CnH2n+2
First 10 alkanes
Structural modelsStructural models
Isomers
• Same chemical formulas but different configurations.
• Will have Different properties !
"straight"
chain
C - C - C - C
branched
chain
C - C - C
|
C
Unsaturated Hydrocarbons
• Alkenes: contain at least one double bond
• Cn H2n
Alkynes: Contain at least one triple bond
• Formula is : CnHn
• Ethyne
Aromatic Compounds Benzene rings
Monomers
– Monomers are small, simple molecules, mostly organic, that can join with other similar molecules to form very large molecules, or polymers
Polymers
• Polymers are substances composed of multiples of simpler units called monomers.
• Polymers are extremely long chains with an unspecified number of monomer units.
PVC
Types of POLYMERS
• Determined by # of carbon atoms and how atoms are arranged
–Straight chain
–Branched chain
–Cross-linked
Types of Polymer Chains
Natural Polymers
• Carbohydrates• Proteins• Fats• Silk • Cotton• Cellulose• Starch • DNA and RNA
• Chitin • Fingernails• Natural Rubber • spider webs are also
poly-peptides (proteins) and are natural polymers
More Natural Polymers
• cellulose (amylose and amylopectin) proteins silk
•polyhydroxyalkanoates (natural polyesters made by bacteria as food reserves) deoxyribonucleic acid (DNA)
Monomers of Natural Polymers
• Nucleotides DNA and RNA
• Monosaccharides Carbohydrates
• Amino Acids Proteins
Synthetic Polymers:
• Plastics • Nylon • Teflon • Elastic • Styrofoam • Cellophane • Polyurethane • Polyester • Acrylic
Straight chains
• Number of atoms in chain affects the boiling point
• More atoms, higher boiling point
Branched Chain
Polyethylene (branched polymer) magnified 15,000x
Ring Structures
Cross-linking
Crosslinking
• Cross-links are bonds that link one polymer chain to another
• They can be covalent bonds or ionic bonds
Crosslinkingpolymers
When polymer chains are linked together by crosslinks, they lose some of their ability to move as individual polymer chains. For example, a liquid polymer (where the chains are freely flowing) can be turned into a "solid" or "gel" by crosslinking the chains together.
Crude Oil Distillation Unit
OIL SPILLS
Hydrocarbon Combustion
• Combustion is a process that everyone has experienced. It is used to heat homes, to power automobiles, and even to produce electricity. Combustion is an exothermic reaction between oxygen and a hydrocarbon. Combustion requires a certain amount of heat to begin, but once started the reaction proceeds spontaneously generating water vapor and carbon dioxide along with large amounts of energy in the form of heat and light.
The Combustion Equation:
Complete Combustion of Methane:
CH4 + 2O2 CO2 + 2H2O
Methane + Oxygen Carbon Dioxide + Water
methane + oxygen carbon monoxide + water.2CH4(g) + 3O2(g) 2CO(g) + 4H2O(l)
Incomplete Hydrocarbon Combustion
• http://science.howstuffworks.com/oil-refining4.htm