180 likes | 349 Views
Chapter 20 Hydrocarbon Compounds. Organic naming. Hydrocarbons contain only two elements: hydrogen and carbon Carbon has 4 valence electrons, thus forms 4 covalent bonds not only with other elements, but also forms bonds WITH ITSELF.
E N D
Chapter 20 Hydrocarbon Compounds Organic naming
Hydrocarbons contain only two elements: hydrogen and carbon • Carbon has 4 valence electrons, thus forms 4 covalent bonds • not only with other elements, but also forms bonds WITH ITSELF.
Names recommended by IUPAC - the International Union of Pure and Applied Chemistry
Prefixes for carbon meth - one eth - two prop - three but - four penta - five hexa - six hepta - seven octa - eight nano - nine deca - ten
Alkanes • Single bonded carbon C-C-C C-C-C-C etc. Formula: Cn H2n + 2
Alkanes • Many alkanes used for fuels: methane, propane, butane, octane • The first 4 are gases; #5-10 are liquids; higher alkanes are solids
Alkenes • Hydrocarbons containing carbon to carbon double bonds are called alkenes C=C C-C=C • Called “unsaturated” if they contain double or triple bonds • Formula: • CnH2n
Alkynes • Hydrocarbons containing carbon to carbon triple bonds called alkynes -C C- • Alkynes are not plentiful in nature • Formula: Cn H2n - 2
Name the following: H H C H C H H H
Name the following: H H H H C C C H H H H
H H H H H H C C C C C H H H H H H
H H H H C C C C C H H H H
H H H H H H C C C C C H H H H
Branched-Chain Alkanes • Branched-chain means that other elements besides hydrogen may be attached to the carbon • Halogens (bromine becomes bromo, fluorine becomes fluoro), oxygen, nitrogen, sulfur, etc. • Position of these elements are in the name
Branched-Chain Alkanes • A hydrocarbon substituent is called an alkyl group • use the same prefixes to indicate the number of carbons, but the -ane ending is now -yl • -CH3 methyl, • -CH2CH3 ethyl, • -CH2CH2CH3 propyl, etc.
Branched-Chain Alkanes • Rules for naming 1. Longest chain is parent 2. Number, so that the branches have the lowest # 3. Give position number to branch 4. Prefix more than one branch 5. Alphabetize branches 6. Use proper punctuation ( - , )
From the name, draw the structure: 1. Find the parent, with the -ane 2. Number carbons on parent 3. Identify substituent groups; attach 4. Add remaining hydrogens
3-ethylpentane • 2,3,4-trimethylhexane • Pentene