Lesson 1: Organic Chemistry

Hydrocarbons Crash course Nomenclature Crash course Alkenes and alkynes Crash course

ORGANIC COMPOUNDS Are compounds containing the element carbon… that bond to one another to form chains, rings, and networks. Notice that carbon forms the skeleton of the molecule Iso-butane Propane Benzene

ORGANIC COMPOUNDS C4H10 C3H8 C6H6 Usually have C in Front of their formulas C4H10 C6H6 Iso-butane C3H8 Propane C6H6 Benzene

ORGANIC COMPOUNDS Methane CH4 Tetrahedral ethene shape C2H4 A Carbon atom always forms a total of four bonds with other atoms. Creates a characteristic shape: Double bond 1 1 4 4 Methane CH4 2 3 3 2 1 4 3 2 Tetrahedral shape ethene C2H4

ORGANIC COMPOUNDS Usually form… Covalent bonds with nonpolar molecules They are usually Gases, liquids OR waxy solids with low melting points Remember? Weak London IM forces ( big and sticky forces)

ORGANIC COMPOUNDS Usually Not soluble in water (oily or waxy) unlikes don’t dissolve

ORGANIC COMPOUNDS Usually Non-electrolytes (except acids-COOH) HC2H3O2 / CH3COOH (aq)

Usually have Slow reactions With high activation energies

ORGANIC COMPOUNDS contain only carbon and hydrogen. Hydrocarbons are the simplest: contain only carbon and hydrogen.

Homologous series: Series of compounds with similar structures Members vary by adding more carbons to the chain Will have similar properties Properties vary slightly from one member to the next 1 carbon Methane 2 carbons ethane 3 carbons propane 4 carbons butane

Homologous series: 3 carbons propane 4 carbons butane

HOMOLOGOUS SERIES Major series include the alkanes, alkenes and alkynes. Members differ by 1 C and 2 H’s: CH2

Homologous series: ALKANES Contain all single bonds between carbon atoms in the chain. Have the general formula CnH2n+2 where “n” equals the number of carbon atoms in the chain. Member’s names always ends in “ane”. The number of carbons in the chain determines the prefix to put in front of the name ending. C4H10 C4H2(4) + 2 But ane

C1H4 = CH4 methane C2H6 ethane C3H8 propane Etc.

pentane Pent = 5 C ane = alkane CnH2n+2 C5H2(5)+2 C5H12

Ethane Propane C3H8 C2H6 C2H2(2)+2 H H H C C H H H Heptane C7H16

So what is the name of this compound? A “methyl” group Address: #2 Carbon On a propane “chain” (C4H10) So what is the name of this compound? It has the same formula as butane But it has a different structure 2-methyl propane Its an Isomer (I-som-er)

ISOMERS Compounds that have the same molecular formula but have a different structure. Isomers will have different physical and chemical properties. Also, the greater the number of carbons in a chain, the more isomers possible.

Naming ISOMERS 1. Name the Longest Carbon Chain: 3 so it is a Propane. OR 2 3 1 3 2 1 1. Name the Longest Carbon Chain: 3 so it is a Propane. 2. Number the Longest Carbon chain for identifying bond location 3. Group Comes Off 2nd Carbon so its address is 2-. 4. Side Group has 1 Carbon so it is “Methyl” group so . .

Naming ISOMERS 2-methyl propane (it is an isomer of butane).

IUPAC RULES FOR NAMING COMPOUNDS Name the longest carbon chain. Number the carbons in the chain so side groups can be “addressed”: (direction uses lowest whole numbers possible) Determine the names of side groups. carbon groups start with a prefix, then add “yl”. if more than one of the same side group appears, prefixes telling the number of side groups are used (di, tri, tetra, etc.).

TRY THESE: n-PENTANE 2, 2 DIMETHYL PROPANE 1 2 3 n-PENTANE “normal” pentane Count and name the longest chain. What side groups and their addresses? 2, 2 DIMETHYL PROPANE

TRY THESE: Still 2,2 dimethyl propane 1 2 3 Notice: you could number the chain vertically? Still 2,2 dimethyl propane

Name this:

Name this:

Name this:

Hint: move a carbon from the end to the middle of the chain Make a 4 carbon chain with a 1 carbon group: “methyl butane”

SATURATED COMPOUNDS Hydrocarbons containing only single carbon-carbon bonds – (have all “bond sites” occupied) the members of the alkane series. Butane is saturated with hydrogen

Unsaturated = are missing H’s from the chain Has a double bond between C atoms Missing H’s here C3H6 Prop- ene

Unsaturated = are missing H’s from the chain These are all unsaturated Can you spot the empty bond sites?

UNSATURATED COMPOUNDS Hydrocarbons containing double and/or triple carbon-carbon bonds. Involves two or three shared pairs of electrons between carbon atoms. Members of the alkene and alkyne series. When naming unsaturated hydrocarbons, the placement of the double or triple bond must be identified.

ALKENES Contain one double bond between carbon atoms in the chain. Have the general formula CnH2n. Member’s names always ends in “ene”. First member is ethene. C2H4

ALKYNES Contain one triple bond between carbon atoms in the chain. Have the general formula CnH2n–2. Member’s names always ends in “yne”. Number address of triple bond. First member is ethyne. C2H2

1 propene 1 butyne 2 butyne Name These Compounds: 1 2 3 1 2 3 4 1 2 3

Name this:

Name this:

Name this:

One more:

Hint: draw it and see if you need a double or triple bond so each C has four bonds Hint: see above hint