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Department of Chemistry CHEM1020 General Chemistry *********************************************** Instructor: Dr. Hong Zhang Foster Hall, Room 221 Tel: 931-6325 Email: [email protected] CHEM1020/General Chemistry _________________________________________ Chapter 9. (L4)-Organic Chemistry.
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..Introduction to functional groups
…Review of electronic structure of chlorine atoms
Valence electronic structure of Cl:
Cl has one single unpaired electron available for bonding ..
Cl is much like H in this way: ·H, ·Cl:
…If hydrocarbons have chlorine atoms as a new component, then they are different new organic compounds.
…Because of the similarity between Cl and H in bonding (forming one single covalent bond), Cl can replace H in many hydrocarbons with identical carbon skeletons and structures
Examples of hydrocarbons:
alkanes: Replacing H with Cl in a CH4
CH3Cl, methyl chloride, or chloromethane
CH2Cl2, dimethyl chloride, or dichloromethane or methylene chloride
CHCl3, trimethyl chloride, or trichloromethane, or chloroform
CCl4, tetramethyl chlordie, tetrachloramethane, or carbon tetrachloride
…Chlorinated hydrocarbons can cause severe liver damage
…Some uses of chlorinated hydrocarbons can be found on pp.248
…DDT (dichlorodiphenyltrichloroethane), highly toxic insecticides, banned now,
PCBs, polychlorinated biphenyls
…All chlorinated hydrocarbons have similar properties, and mostly toxic
…Carbon compounds containing fluorine and chlorine are called CFCs.
CFCs have been used as dispersing gases in aerosol cans for making foamed plastics and as refrigerants
Three common CFCs:
CFCl3, named as CFC 11, 1F and 3Cl replacing 4H in a CH4
CF2Cl2, named as CFC 12, 2F and 2Cl replacing 4H in a CH4
CF2ClCF2Cl, named as CFC 114, 4F and 2Cl replacing 6H in a CH3CH3,
…CFCs are ideal as propellants widely used in aerosol cans for deodorants, hair spray, and food products
…CFCs are very inert, so highly persistent in the environment
…CFCs are bad for the “good ozone” in the atmosphere (discussed in more details later)
…Groups of atoms joined together as special units in organic compounds that cause them to have specific properties and functions are called functional groups
…Usually, organic compounds are classified by their functional groups
Examples of functional groups:
single C-to-C bond
double C-to-C bond
triple C-to-C bond
many others to be learned later
In many cases, a functional group is attached to a hydrocarbon stem called an alkyl group
Examples of alkyl groups:
CH3-, mthyl group, from CH4
CH3CH2-, ethyl group, from CH3CH3
For a short cut, alkyl group can be represented by a single letter, R, which means anyone of the alkyl groups; thus, an organic compound can be represented by
R + functional group
Chlorinated hydrocarbons are the organic compounds that have
(a) replacement of hydrogen by oxygen;
(b) replacement of hydrogen by nitrogen;
(c) replacement of hydrogen by chlorine;
(d) none of above is right.
Which of the following is a chlorinated hydrocarbon
Which is equivalent to CFC in organic chemistry
(a) Chlorinated fat carbons;
(b) Coal from coast;
(d) none of above.
Which of the following is a CFC compound
Which of the following is a functional groups
Which of the following is a functional groups in organic chemistry
Which of the following is an alkyl group in organic chemistry