Hydrocarbon Compounds

determining the IUPAC name of a cycloalkane

1. count the number of carbons in the ring and assign the corresponding alkane name 2. simply add the prefix cyclo- to the alkane name

naming an alkene by the IUPAC system

1. find the longest chain that contains the double bond. this chain is the parent alkene 2. it has the root name of the alkane with the same number of carbons plus ending -ene 3. the chain is numbered so that the carbon atoms of the double bond have the lowest possible numbers 4. substituents on the chain are named and numbered in the same way they are for alkanes

formula of a branched-chain alkane

1. find the root word (ending in -ane) in the hydrocarbon name 2. then, draw the longest carbon chain to create the parent hydrocarbon, and number the carbons in the chain 3. identify the substituent groups in the hydrocarbon name. attach the substituents to the numbered parent chain at the proper positions 4. complete the structural formula by adding hydrogens as needed

IUPAC rules for naming branched-chain alkanes

1. the name of the branched-chain alkane is based on the name of the longest continuous carbon chain 2. each substituent is named according to the length of its chain and numbered according to its position on the main chain 3. number the carbons in the main chain in the sequence. to do this, start at the end that will give the substituent groups attached to the chain the smallest numbers 4. add numbers to the names of the substituent groups to identify their positions on the chain. these numbers become prefixes to the name of the substituent 5. use prefixes to indicate the appearance of the same group more than once in the structural formula. di-, tetra-, etc. 6. list the names of alkyl substituents in alphabetical order. for purposes of alphabetizing, ignore the prefixes di-, tri-, and so on. ex: 4-ethyl is before 2,3-dimethyl 7. combine all the parts and use proper punctuation. write the entire name without any spaces. use commas to separate numbers, and use hyphens to separate numbers and words

aromatic compound

AKA arene; an organic compound that contains the benzene ring structure and may have a pleasant or unpleasant odor and flavor benzene is the simplest aromatic compound

what are the three smallest alkyl groups

CH3 methyl CH2CH3 ethyl C3H7 propyl

what is the difference between a straight-chain alkane and a branched-chain alkane?

SCA: contains any number of carbon atoms bonded in a chain. carbon atoms are bonded to either one or two other carbons BCA: can have one or more alkyl groups attached to it. its carbon atoms can be bonded to one, two, three, or four other carbons

cyclic hydrocarbon

a compound that contains a hydrocarbon ring can be saturated or unsaturated, just like straight-chain and branched-chain alkanes

homologous series

a group of compounds in which there is a constant increment of change in molecular structure from one compound in the series to the next a CH2 group is the increment of change in straight-chain alkanes

alkane

a hydrocarbon containing only single covalent bonds. ex: methane and ethane

alkyl group

a hydrocarbon substituent that is derived from an alkane/an alkane with one of the hydrogens removed they are named by removing the -ane ending from the parent hydrocarbon name and adding -yl

alkene

a hydrocarbon that contains one or more carbon-carbon double covalent bonds unsaturated compound

alkyne

a hydrocarbon that contains one or more carbon-carbon triple covalent bonds shown as three parallel lines like alkenes, are unsaturated compounds

structure of benzene

a six-membered carbon ring with one hydrogen atom attached to each carbon this arrangement leaves one electron from each carbon free to participate in a double bond this means that there is resonance

straight-chain alkane

an alkane that contains any number of carbon atoms, one after the other, in a chain. ex: propane and butane

branched-chain alkane

an alkane with one or more alkyl groups attached to the parent structure

substituent

an atom or group of atoms that can take the place of a hydrogen atom on a parent hydrocarbon molecule atoms such as halogens, oxygen, and nitrogen can be substituents

hydrocarbon

an organic compound that contains only one carbon and hydrogen simplest organic compounds the two simplest hydrocarbons are methane and ethane. methane (CH4) is the major component of natural gas

saturated compound

an organic compound that contains the maximum number of hydrogen atoms per carbon atom alkanes are saturated compounds because the only bonds in alkanes are single covalent bonds

unsaturated compound

an organic compound with one or more double or triple carbon-carbon bonds the ratio of the hydrogen atoms to carbon atoms is lower in an unsaturated compound then in a saturated compound

aliphatic compound

any compound not classified as an aromatic compound. ex: alkanes, alkenes, alkynes, and cycloalkanes properties are very different from aromatic compounds

note

at least one carbon-carbon bond in an alkene is a double covalent bond. other bonds may be single carbon-carbon bonds and carbon-hydrogen bonds

note

at least one carbon-carbon bond in an alkyne is a triple covalent bond. other bonds may be single or double carbon-carbon bonds and carbon-hydrogen bonds

branched-chain alkanes

because carbon atoms form four covalent bonds

why does a carbon atom form four covalent bonds?

because carbon has four valence electrons

what does the able of carbon to form stable carbon-carbon bonds allow?

carbon can form so many different compounds

what are the structural characteristics of alkenes?

carbon-carbon double covalent bond(s)

cycloalkane

cyclic hydrocarbon that contains only single bonds (saturated)

what is the simplest alkene?

ethene (C2H4) it is often called by the common name ethylene

what is the difference between ethene and ethyne?

ethene: alkene containing two carbons in a carbon-carbon double bond ethyne: alkyne containing two carbons in a carbon-carbon triple bond

note

in a benzene molecule, the bonding electrons between carbon atoms are shared evenly around the ring benzene and other molecules that exhibit resonance are more stable than similar molecules that do not exhibit resonance. thus benzene is not as reactive as six carbon alkenes

what are the different ways of representing hydrocarbons?

methane and ethane

note

not all hydrocarbons are straight chains or branched chains the in some hydrocarbon compounds, the carbon chain is in the form of a ring

when benzene is a substituent, it is called _____________.

phenyl (comes before hexane)

carbons in branched-chain alkanes

primary, secondary, tertiary, or quaternary

what is the difference between propane and propene?

propane: an alkane with 3 carbons and no carbon-carbon double bonds propene: an alkene with 3 carbons and one carbon-carbon double bond

complete structural formula

shows all the atoms and bonds in a molecule

condensed structural formula

some bonds and/or atoms are left out of the structural formula - although the bonds and atoms do not appear, you must understand that they are there sometimes works just as well as complete structural formula

CH3 (CH2)n CH3

the CH2 is a methylene group the n indicates the number of methylenes

organic chemistry includes_________

the chemistry of almost all carbon compounds, regardless of their origin

what types of compounds are included in the study of organic chemistry?

the chemistry of almost all carbon compounds, regardless of whether they are synthesized by living organisms or from inorganic substances

properties of hydrocarbons

the electron pair in a carbon-hydrogen or a carbon-carbon bond is shared almost equally by the nuclei of the atoms forming the bond thus, hydrocarbons are nonpolar molecules

parent alkane

the longest continuous carbon chain of a branched-chain hydrocarbon

straight-chain alkanes

the names of the straight-chain alkanes follow rules established by the IUPAC every alkane has a name that ends with the suffix -ane CH4 methane C2H6 ethane C3H8 propane C4H10 butane C5H12 pentane C6H14 hexane C7H16 heptane C8H18 octane C9H20 nonane C10H22 decane Cn H 2n+2

why is methane not typical of the vast majority of organic compounds?

there isn't a bond between carbon atoms in a methane molecule

what are two possible arrangements of carbon atoms in an alkane?

they can be arranged in a straight chain or in a chain that has branches

how many hydrogen atoms will a cycloalkane contain in comparison to a straight chain alkane with the same number of carbons?

two fewer because one additional carbon-carbon bond in cycloalkane

how do saturated and unsaturated fats differ structurally?

unsaturated: contains double or triple carbon-carbon bonds