Chapter 11 Organic Compounds Alkanes ORGANIC COMPOUNDS In
- Slides: 40
Chapter 11 Organic Compounds: Alkanes
ORGANIC COMPOUNDS • In 1828, Friedrich Wöhler first synthesized an organic compound from an inorganic source. • This discredited the “vital force” theory.
ORGANIC CHEMISTRY • Organic chemistry • Inorganic chemistry • The principle components of food, fuels, wood construction, and clothing are ________.
ORGANIC CHEMISTRY (continued) • An estimated 500, 000 _________ have been identified, but more than 9 million _________ are known, and thousands of new ones are synthesized or isolated each year.
HUND'S RULE
BONDING CHARACTERISTICS
ATOMIC ORBITALS
BONDING CHARACTERISTICS (continued) • An sp 3 orbital has a two-lobed shape, similar to the shape of a _______ but with different-sized lobes. • Each carbon-hydrogen bond in methane arises from an overlap of a C ____ and an H _______ orbital. • The sharing of two electrons in this overlap region creates a _______
BONDING CHARACTERISTICS (continued) • The four hybrid sp 3 orbitals allow carbon to form ____ bonds. When carbon is joined to four substituents (______), the resultant configuration is _______ in shape.
BONDING CHARACTERISTICS (continued) • Carbon can also bond to other carbon atoms. • In principle, there is no limit to the number of carbon atoms that can bond covalently. • Organic molecules range from the simple molecules like CH 4 to very complicated molecules containing over a million carbon atoms.
ISOMERISM • _______: Compounds that have identical molecular formulas, but different arrangement of atoms. • _________: A type of _______ in which the atoms bond in different patterns. • Isomers of C 2 H 6 O:
FUNCTIONAL GROUPS • __________are unique reactive combinations of atoms that differentiate organic compounds of one class from those of another. • Examples:
FUNCTIONAL GROUPS (continued)
FUNCTIONAL GROUPS (continued)
REPRESENTING ORGANIC COMPOUNDS • Expanded structural formulas • Condensed structural formulas
CLASSIFICATION OF HYDROCARBONS • _________ are organic compounds that contain only carbon and hydrogen. • A ________ that contains only single bonds is a saturated hydrocarbon or ______. • Unsaturated hydrocarbons are called ________________ and contain double bonds, triple bonds, or ring systems with alternating double bonds.
CLASSIFICATION OF HYDROCARBONS (continued)
ALKANES • Alkanes can be represented by the general formula Cn. H 2 n+2, where the n is the number of carbon atoms in the molecule. • The simplest alkane is _________, which is the primary compound in natural gas.
ALKANES (continued) • More complex alkanes can be C—C—C C | C—C—C | C
ALKANES (continued)
CONFORMATIONS OF ALKANES • . • The different arrangements of atoms in space achieved by rotation about single bonds are called _______.
CONFORMATIONS OF ALKANES (continued) • This figure shows perspective models and carbon skeletons of two conformations of n-butane.
CONFORMATIONS OF ALKANES (continued) • Which of the following pairs represent structural isomers, and which are simply the same compound? • Which are normal alkanes and which are branched alkanes?
CONFORMATIONS OF ALKANES (continued)
CONFORMATIONS OF ALKANES (continued)
ALKYL GROUPS • An alkyl group is a group differing by one hydrogen from an alkane.
COMMON NONALKYL GROUPS
NAMING ALKANES • The IUPAC method consists of: Root
NAMING ALKANES (continued) • Step 1: Identify and name the longest carbon chain. This gives the root and ending. (The ending –ane signifies the alkane family. ) • Step 2: Number the longest carbon chain to give the lowest number to any carbon to which a group is attached. 5 CH CH 3 | | Example: CH 2 — CH 3 (pentane) 4 3 3 2 1 • Step 3: Locate and name the attached alkyl groups. • Step 4: Combine the longest chain and the branches into the name. 2 -methylpentane
NAMING ALKANES (continued) • Step 5: • For multiple branches, show the location of each branch with numbers. • For multiple branches of the same type, modify the name with di-, tri-, tetra-, penta-, etc. and separate the position numbers by commas. • List multiple branches alphabetically. Ignore the di-, tri-, sec-, and t- prefixes. Example: 1 CH 3— 2 CH — 3 CH — 4 CH — 5 CH 2 — 6 CH 2 — 7 CH 3 | | | CH 3 CH–CH 3 | CH 3 4 -isopropyl-2, 3 -dimethylheptane
THE SHAPE OF CYCLOALKANES
THE SHAPE OF CYCLOALKANES (continued)
NAMING CYCLOALKANES • Cycloalkanes are alkanes containing rings of carbon atoms. • The prefix cyclo- is used before the alkane name. • When two or more substituents are attached to the cycloalkanes, the ring numbering begins with the first group alphabetically and proceeds to give lowest numbers possible. Example: CH 2 CH 3 1 CH 3 3 2 1 -ethyl-3 -methylcyclopentane
ISOMERISM & CYCLOALKANES • Stereoisomers are compounds with the same structural formula but different spatial arrangements of atoms. • Geometric isomers are molecules with restricted rotation around C-C bonds that differ in the three-dimensional arrangements of their atoms in space and not in the order of linkage of atoms. • Rotation about C-C single bonds occurs in open-chain compounds but not within rings.
ISOMERISM & CYCLOALKANES (continued) • Two geometric isomers exist for 1, 2 -dimethylcyclopentane. • Cis-substituents are on the same side of the ring. • Trans-substituents are on the opposite sides of the ring.
PHYSICAL PROPERTIES OF ALKANES • • • Non-polar molecules with weak intermolecular forces Not soluble in water (hydrophobic) Low density (less dense than water) Melting points increase with molecular size Boiling points increase with molecular size
PHYSICAL PROPERTIES OF ALKANES (continued) • A homologous series is a group of compounds with the same functional class that differ by a –CH 2– group.
PHYSICAL PROPERTIES OF ALKANES (continued)
ALKANE REACTIONS • Alkanes are the least reactive of all organic compounds. • The most significant reaction of alkanes is combustion (rapid oxidation). • Many alkanes are used as fuels. • Methane – natural gas • Propane – used in gas grills • Butane – lighters • Gasoline – a mixture of hydrocarbons
ALKANE REACTIONS (continued) • Complete Combustion (in the presence of adequate oxygen) CH 4 + 2 O 2 → CO 2 + 2 H 2 O + 212. 8 kcal/mol • Incomplete Combustion (not enough oxygen available) 2 CH 4 + 3 O 2 → 2 CO + 4 H 2 O CH 4 + O 2 → C + 2 H 2 O
- Alkanes solubility
- Isomers of pentane
- Alkane chemical formula
- Uses of alkanes
- Alkanes list
- General formula for alkyl group
- Alkanes alkenes alkynes
- 3-butyl-3-propyl-1-pentyne
- Ir spectra of alkanes
- Combustion of alkynes
- Combustion complete and incomplete
- Covalently def
- Alkylation of alkanes
- Viscosity of alkanes
- Cyclopentane uses
- Iupac stands for
- Bond angle in cyclohexane
- Alkanes in bromine water
- Organic chemistry nomenclature
- How many valence electrons does it have
- Applications of alkanes
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- Four major groups of organic compounds
- Decomposition of organic matter equation
- Charring test of organic and inorganic compounds
- Organic combustion
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- Importance of organic compounds
- Difference between organic and inorganic
- Purification and characterization of organic compounds
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- Organic vs inorganic compounds
- What is the classification of organic compounds
- Carbon compound
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- Organic compounds grade 10 life science
- Organic halogen compounds