Unit X Organic Chemistry Shelly Wei Mathew Jiang Johnny Yu Mike Chi
A prior question: What is ORGANIC CHEMISTRY? Organic Chemistry: It is a chemistry sub-discipline involving the scientific study of the structure, properties, and reactions of organic compounds and organic materials, i.e. matter in its various forms that contain… Carbon Atoms!
*Review Questions* What is functional groups? • Functional Groups: A Functional group is a specific group of atoms which exists in a molecule and gives a molecule an ability to react in a specific manner or gives it specific properties. Different groups of atoms have different manner or properties.
Any Examples of functional groups? • Halides • Carbon-carbon double bonds (in alkenes) • Carbon-carbon triple bonds (in alkynes) • Alcohol • Aldehydes • Ketones • ….
Now… • There is something that can also be categorized into functional groups, and it is called… Ether!
Organic Chemistry LessonCarboxylic Acids Mathew Jiang Mike Chi
What kind of substance would you judge only after your smelling? • Yes, it is… Vinegar!
What is carboxylic acid? “Organic Acids” • Carboxylic Acid: It is an organic compound which contains a COOH group. The COOH group is also sometimes shown as… What is R? R is a monovalent functional group. Something that possesses a charge of -1.
How to name it? • Let me show you some examples… • CH3COOH • HCOOH • CH3-CH2-CH2-COOH • Ethanoic acid • Methanoic acid • Butanoic acid Why? Find the regulation?
How many carbons are there in carboxylic acid? • The number of carbons Prefixes • Prefix + oic + Acid • That is how the name comes from!
Practice Problems • Pg.240 #37 Just identify which are the carboxylic acids?
What is an ether?? • A compound in which an oxygen joins two hydrocarbon groups • Several ethers have anaesthetic properties: ethoxyethane was formerly used in hospitals and is still used by biologists to “quiet” or anaesthetize insects
Physical Properties-4 kinds • Physical state: Methoxy methane and methoxy ethane are gases while other members are volatile liquid with pleasant smell. • Dipole moment:Bond angle of ether is due to hybridisation of oxygen atom. Since C – O bond is a polar bond, hence ether possess a net dipole moment, even if they are symmetrical. dipole moment of dimethyl ether is 1.3 D and dipole moment of di ethyl ether is 1.18 D. • Boiling points: Boiling points of ethers are much lower than those of isomeric alcohols, but closer to alkanes having comparable mass. This is due to the absence of hydrogen bonding in ethers. • Solubility: Solubilities of ethers in water are comparable with those of alcohols.
Examples • Di ethyl ether and n-butyl alcohol have approximately the same solubility in water. This is because, ether form hydrogen bond with water much in the same way as alcohol do with water. • Solubility of ether in water decreases with the size of alkyl groups.
Exercises • Which of the following are isomers? (a) Methyl alcohol and dimethyl ether (b) Ethyl alcohol and dimethyl ether (c) Acetone and acetaldehyde (d) Propionic acid and propanone Answer: B
Exercises • Oxygen atom in ether is? (a) Very active (b) Replaceable (c) Comparatively inert (d) Active Answer: C