Intro to organic chemistry: MCQ 3

Organic Chemistry

• Organic chemistry is the study of carbon compounds, which are essential for all living things.
• Carbon has a valency of 4, allowing it to form 4 bonds.
• Organic compounds can be synthesized in a lab and are used in various industries, such as pharmaceuticals, fibers, and fuels.

Carbon Chains and Rings

• Carbon can form stable chains and rings, allowing for the existence of millions of organic compounds.
• Carbon chains can be straight or branched, and can have different lengths.

Naming Organic Compounds

• The name of an organic compound is based on the number of carbons present, the type of bonds formed, and the functional group present.
• The number of carbons present in the main chain determines the 1st part of the compound's name:
  • 1 carbon: meth
  • 2 carbons: eth
  • 3 carbons: prop
  • 4 carbons: but
  • 5 carbons: pent
  • 6 carbons: hex
  • 7 carbons: hept
  • 8 carbons: oct
  • 9 carbons: non
  • 10 carbons: dec
• The functional group contributes to the 2nd part of the name:
  • Alkanes: (al)
  • Alkenes: (ene)
  • Alkynes: (yne)
  • Alcohols: (ol)
  • Aldehydes: (al)
  • Ketones: (one)
  • Carboxylic Acids: (oic acid)
  • Esters: (oate)

Functional Groups

• Alkanes: C-C and C-H single bonds only
• Alkenes: has a C=C double bond
• Alkynes: has a triple bond
• Alcohols: contains an OH (hydroxyl group)
• Aldehydes: contains a CHO group at the end of the molecule
• Ketones: C=O cannot be at either end of the molecule, must be in the middle
• Carboxylic Acids: COOH group at the end of the molecule
• Esters: COOC in the middle of the molecule
• Aromatic Compounds: contain a benzene ring in their structure

Naming Esters

• 1st part: the name of the alcohol component
• 2nd part: the name of the acid component

Side Chains

• Side chains come off the main carbon chain and play a part in naming an organic compound
• An alkyl group can be:
  • Methyl: CH₃
  • Ethyl: C₂H₅
  • Propyl: C₂H₇
• Halogens can also occur in organic compounds:
  • Chloro: Cl
  • Bromo: Br
  • Iodo: I

Naming Compounds with Side Chains

• Naming the side chain:
  • If two identical side chains exist, a di prefix is given to the side chain and the positions of these side groups must be recorded
• Assigning positions to the side chains:
  • The carbons are numbered starting from the end that gives the side chain the lowest possible numbers
  • The name of the compound is based on the positions of the side chains

Bonding Position

• The position of the functional group in alkenes, alkynes, alcohols, and ketones affects the naming of the compound
• The position of the double bond in alkenes and alkynes does not change the compound's name

The Longest Carbon Chain

• Organic molecules must be named after the longest chain of carbons
• The longest chain of carbons determines the 1st part of the compound's name

Structural Isomers

• Structural Isomers are compounds with the same molecular formula but different structural formulas
• Example: butane (C₄H₁₀) and 2-methylpropane (C₄H₁₀) are structural isomers