alkanes, alkenes and alkynes
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Alkanes, Alkenes and Alkynes . SCH4U Spring 2012. Alkanes. Single covalent bonds Saturated hydrocarbons Nonpolar Not soluble in water Soluble in benzene and other non-polar solvents General formula: C n H 2n+2 (n represents the number of carbon atoms). Alkanes - Examples. - PowerPoint PPT PresentationTRANSCRIPT
Alkanes, Alkenes and Alkynes
SCH4U Spring 2012
Single covalent bonds Saturated hydrocarbons Nonpolar Not soluble in water Soluble in benzene and other non-polar
solvents General formula: CnH2n+2 (n represents the
number of carbon atoms)
Alkanes
Alkanes- Examples
e.g. C4H10
Empirical molecular formula C4H10 Expanded molecular formula CH3CH2CH2CH3 Structural formula
Condensed structural formula CH3-CH2-CH2-CH3 Line structural formula
Ways to represent structures
Three basic parts:
Root: denotes the number of carbon atoms in the longest continuous chain of carbon atoms
Prefix: gives the positions and names of any branches from the main chain
Suffix: indicates the series to which the molecule belongs (e.g. –ane)
IUPAC name of organic compounds
Root and side group names
Identify the root Identify the longest continuous chain Find the root for the number of carbons in the chain
Identify the suffix
Identify the prefix Identify the number of carbon atoms in each side group and determine the name If there is more than one type of side group, write their names in alphabetical
order Find the position of each side group. Numbering must begin at the end of the
main chain that will give the side groups the lowest possible numbers Use a hyphen to separate numbers and words and use a comma to separate the
numbers Use a prefix to indicate how many of each type of side group are present if there
is more than one of the same side group (e.g. di-, tri-, tetra-)
Name the compound
Naming Alkanes
Name the following molecules
Questions
Identify the root Identify the suffix Draw and number the main chain, but do
not add any hydrogen atoms yet Identify the prefix and draw the side groups Add hydrogen atoms
Drawing Alkanes
Draw the condensed formula for • 2-methylbutane• 2,2-dimethyl-3-propyloctane
Draw the line structural formula for• 3,3,4-triethylnonane• 3,3,4,4-tetramethyldecane
Questions
Small alkanes are gases at standard temperature
Medium-length alkanes are liquids at standard temperature
Very large alkanes are waxy solids The larger the alkane, the higher the boiling
point
Physical properties of alkanes
At least one double bond in the carbon chain
At least two carbon atoms Unsaturated hydrocarbons Non-polar Do not dissolve in water General formula (one double bond): CnH2n
Alkenes
Identify the root• Identify the longest continuous chain that contains the double bond• Find the root for the number of carbons in the chain
Identify the suffix• Number the main chain by starting at the end of the chain nearest
the double bond• If the alkene contains four or more carbons, give the position of the
double bond by indicating the number of the carbon atom that precedes the double bond. The suffix consists of a hyphen, the number and -ene
Identify the prefix
Name the compound
Naming Alkenes
Name each alkene
Questions
Draw the condensed structural formula for• 3-propylhept-2-ene• 4-ethyl-2,5-dimethyloct-3-ene
Draw a line structural formula for• 2-methylbut-1-ene• 4-ethyl-4,5-dimethylhex-1-ene
Questions
The first three alkenes are all gases at standard temperature
Intermediate size alkenes are liquids Boiling points of the alkenes are slightly
lower than those of the alkanes that have the same number of carbon atoms
Physical properties of alkenes
At least one triple bond Unsaturated hydrocarbons non-polar Insoluble in water General formula: CnH2n-2
Alkynes
Draw the condensed structural formula for:• But-2-yne• 4-ethyl-4-methylhept-2-yne
Draw a line structural formula for • 4,5-dimethylhex-1-yne• 2,5,7-trimethylnon-3-yne
Questions
First few alkynes exist as gases at standard temperature
Higher boiling point than the corresponding alkanes
Physical properties of alkynes