Presentation on theme: "Or functional groups. Functional groups Functional groups are parts of molecules that result in characteristic features. Many functional groups exist,"— Presentation transcript:
or functional groups
Functional groups Functional groups are parts of molecules that result in characteristic features. Many functional groups exist, we will focus on about 4.
Organic compounds having functional groups Alcohols Carboxylic acids Amino acids carbohydrates
1. Alcohols a class of organic compounds with an –OH (hydroxyl ) functional group. thus R-OH is the formula (The symbol R is used to represent any carbon chains or rings).
Alcohols condensed structural IUPAC common formula formula name name H – C – O – H H H CH 4 O methanol Methyl alcohol C2H6OC2H6O H – C – C - O – H H H H H ethanol Ethyl alcohol
Alcohols condensed structural IUPAC common formula formula name name H C2H6O2C2H6O2 ethanediol Ethylene glycol C3H8O3C3H8O3 propanetriol glycerol H – C – C – H OH H H – C – C - C – H H OH H H
Naming alcohols For IUPAC: – drop the -e ending of the parent alkane name; add the ending -ol. – Ethaneethanol H – C – C - O – H H H H H
Naming alcohols Alcohols containing 2, 3, and 4 of the - - OH groups are named diols, triols, and tetrols respectively. H – C – C - C – H H OH H H propanetriol
Naming alcohols Common names: – name the alkyl group, then followed by the word alcohol. – One carbon alcohol = methyl alcohol H – C – O – H H H
Properties of alcohols Much like water, alcohols are capable of forming hydrogen bonding between molecules. This means – they will boil at a higher temp. than alkanes with a comparable number of C atoms. – Alcohols of up to 4 carbons are soluble in water in all proportions.
2. Carboxylic acids Functional group: - COOH or (carboxyl group) General formula: R-COOH weak acids (ionize slightly) - C – OH O
Carboxylic acids Named by replacing the -e ending of the corresponding alkane name with - oic and followed by the word acid methanoic acid; ethanoic acid.
Carboxylic acids condensed structural IUPAC common formula formula name name CH 2 O 2 methanoic acid Formic acid C2H4O2C2H4O2 Ethanoic acid Acetic acid H - C – OH O H – C -C – OH O H H
3. Amino acids Functional groups: - NH 2 (amino) and - C – OH O (carboxyl).
Amino acids condensed structural common formula formula name C 2 H 5 NO 2 glycine alanine H 2 N - C - C – OH O H H O H CH 3 C 3 H 7 NO 2
4. Carbohydrates The functional group is or - C – O (carbonyl) -C – H O (aldehyde).
Carbohydrates fructose HO – C – H C = O H – C – OH H H HO – C – H H – C – OH H – C = O H – C – OH H Glucose, C 6 H 12 O 6
Hydrophilic groups Hydrophilic means water loving. Hydrophilic groups are electrically polarized. This makes the substances including a hydrophilic group soluble in polar solvents like water. Examples: - OH, - COOH, - NH 2
Hydrophobic groups Hydrophobic means water hating. Hydrophobic groups are not electrically polarized. Therefore, hydrophobic substances are not soluble in water but soluble in non- polar solvents like benzene. Examples: alkanes, ethylene, acetylene, CCl 4, oils, and fats.
Hydrophilic and hydrophobic groups The common soap is the Na salt of stearic acid. Its formula is: CH 3 (CH 2 ) 16 COONa. When it dissolves in water, it produces Na + and CH 3 (CH 2 ) 16 COO - ions. – CH 3 (CH 2 ) 16 COO - Hydrophobic tail Hydrophilic head
Hydrophilic and hydrophobic groups oil Micelle Hydrophobic tails dissolve oil. Hydrophilic heads stay away from oil but attracted by water molecules. So, the oil is washed away by soap and water.