5.3 - Organic Compounds organic compounds always contain carbon, and usually contain hydrogen (may also include other metals / non-metals) some organic compounds are naturally occurring, others can be made in labs (ie. used in materials for building / clothing) C is written before H in the formulae of organic molecules, to differentiate them from acids (which almost always start with H). Most organic compounds are not acids. Ex. HCl is an acid vs. CH 4 is a hydrocarbon H on left H on right

Carbon in Organic Compounds C has four valence electrons, which allows for more chemical bonding possibilities than any other element  in almost all organic compounds, C is bonded to:  H atoms  other C atoms  other elements close to C on the PT (ie. O, N, S, P, halogens)

Carbon in Organic Compounds because C can form 4 bonds, it can form  ring,  cage, and  branched-chain structures long carbon chains form petroleum and plastics FYI… the formula CH 3 (CH 2 ) n CH 3 represents polyethylene (used for sandwich wrap), when n ≈ 5000 !

Inorganic Compounds …are compounds that do not contain carbon, as well as some exceptions to the organic classification. Examples of some exceptions containing C:  oxides: CO 2, CO  carbonates: CaCO 3 inorganic compounds  carbides: SiC

Organic & Inorganic Compounds

Hydrocarbons A hydrocarbon is an organic compound that contains only carbon and hydrogen.  hydrocarbons are based on a carbon “backbone” / chain, with H atoms added on the sides  The simplest hydrocarbon is methane, followed by…  ethane  propane  butane  pentane  all hydrocarbons are flammable, and most are liquids are room temperature

Various Models of a Simple Hydrocarbon - Methane

Hydrocarbons

Alkanes What is the formula (in terms of the # of carbon atoms and the # of hydrogen atoms) for this family of hydrocarbons? C n H 2n+2  the alkane family dropping one of the H atoms from the formula of an alkane gives a molecular fragment: an alkyl group Ex. Parent AlkaneFormula of Parent Alkane Formula of Alkyl Group methaneCH 4 CH 3 – propaneCH 3 CH 2 CH 3 CH 3 CH 2 CH 2 –

Alcohols alcohols are organic compounds containing C, H and O H and O are “packaged” as a hydroxyl (–OH) group (Note: this is not the same as a hydroxide ion) alcohols are organic compounds with at least one –OH group attached to an alkyl group  the simplest alcohols are methanol (CH 4 O), ethanol (C 2 H 6 O) and isopropyl alcohol (C 3 H 8 O)  alcohols are very good solvents, and are generally very flammable

Alcohols CH 3 CH(OH)CH 3 2-propanol