Oral and Dental Medicine: Hydrocarbons Quiz

Oral and Dental Medicine, Chemistry (BMD1102)

• Course is taught by Prof. Dr. Hossieny Ibrahim.
• Office number is Bio-326.
• Email address is [email protected].
• Course code is BMD1102.

Hydrocarbons

• Hydrocarbons are compounds containing only carbon and hydrogen atoms.
• Aliphatic hydrocarbons are open-chain, saturated, or unsaturated.
• Aromatic hydrocarbons are closed-chain or cyclic, saturated, or unsaturated.
• Saturated hydrocarbons contain only single bonds.
• Unsaturated hydrocarbons contain at least one double or triple bond.
• Alkanes are saturated hydrocarbons.
• Alkenes have one or more double bonds.
• Alkynes have one or more triple bonds.

Alkanes and Cycloalkanes

• Alkanes are the simplest family of hydrocarbons.
• They contain only carbon-hydrogen (C-H) and carbon-carbon (C-C) single bonds.
• The general molecular formula for alkanes is CnH2n+2, where n is the number of carbon atoms.
• The first ten alkanes are methane, ethane, propane, butane, pentane, hexane, heptane, octane, nonane, and decane.
• The molecular formulas and structural formulas for each are provided in the lecture notes.

Shapes of Alkanes

• Different representations (condensed, bond-line, ball-and-stick) are shown for propane, butane, and pentane.

Nomenclature of Alkyl Groups

• Alkyl groups are substituents derived from alkanes by removing one hydrogen.
• They are named with a -yl ending.
• Formulas and names for common alkyl groups are given (methyl, ethyl, propyl, isopropyl, butyl, isobutyl, etc.).

IUPAC Nomenclature of Branched Alkanes

• IUPAC is the International Union of Pure and Applied Chemistry.
• IUPAC nomenclature is a standardized system for naming organic compounds.
• A chemical name typically has four parts: prefix, parent, locant, and suffix.
• The parent chain is the longest continuous carbon chain.
• Substituents (branches) are numbered to give the lowest possible numbers.
• If substituents are equally distant, the next substituent is used to determine the location.
• Rules for naming branched alkanes are provided in detail.

Rules for Naming Branched Alkanes (continued)

• Alphabetical order is used for substituents.
• Prefixes like "di," "tri," are disregarded.
• Only "iso" is used in alphabetizing.
• Substituents are written alphabetically.
• Substituents on the same carbon atom are written using the number twice, e.g., 2,2-dimethyl...

Rules for Naming Branched Alkanes (continued)

• The numerical positions of substituents are listed in increasing order.
• If more than one substituent is present, the substituents are listed alphabetically and followed by their positions.

Solved Problems

• Example structures are given of specific branched alkanes.
• Solutions for these problems are shown.

How to Name Cycloalkanes

• Cycloalkanes are cyclic hydrocarbons where the carbon atoms are arranged in a ring.
• The general molecular formula is CnH2n.
• Cycloalkanes lacking substituents are named by counting carbons in the ring and adding "cyclo" to the beginning of the corresponding alkane name.

How to Name Cycloalkanes (continued)

• Cycloalkanes with one substituent are named by stating the substituent first, followed by the cycloalkane name.

How to Name Cycloalkanes (continued)

• In naming cycloalkenes, the carbon atoms of the double bond are numbered 1 and 2 in the direction that gives the substituent encountered first the smaller number.

Physical Properties of Alkanes

• Alkanes are nonpolar.
• Boiling points increase with increasing number of carbons.
• Boiling points decrease with chain branching.
• The reasons given for these effects are the molecular size, compactness of the molecule, and surface area.

Synthesis of Alkanes and Cycloalkanes

• Hydrogenation is one synthesis method for alkanes.
• Adding H2 to alkenes with catalysts like Pt, Pd, or Ni yields alkanes.

Reactions of Alkanes

• Combustion is the oxidation of hydrocarbons with oxygen to produce heat and CO2 and H2O.
• Halogenation is the replacement of hydrogen by a halogen.
• Temperature and catalysts are required for halogenation.

Halogenation of Higher Alkanes

• The reactivity of various hydrogen atoms being replaced is noted. Primary, secondary, tertiary hydrogen atoms react differently.

Unsaturated Hydrocarbons: Alkenes and Alkynes

• Alkenes and alkynes are hydrocarbons with at least one double or triple bond.
• The lower members of alkenes form oily products when treated using chlorine or bromine.
• The general molecular formula for alkenes is CnH2n.

sp² Hybridization and the Structure of Alkenes

• Detailed explanation, diagrams of hybridization processes, and shapes are shown

Naming Alkenes and Cycloalkenes

• Naming rules for alkenes are presented, involving the longest chain containing the double bond.
• Numerical locations for the double bond must be the lowest values possible.
• Rules for naming cycloalkanes are detailed.

Cis-Trans Isomerism in Alkenes

• Different structures of C4H8 isomers (butenes) are shown.
• Conditions for cis-trans isomerism are described.

Synthesis of Alkenes via Elimination Reactions

• Dehydrohalogenation is the elimination of HX from a haloalkane.
• Dehydration of alcohols is the elimination of water.

Oxidative Cleavage Reactions of Alkenes

• Oxidative reactions like ozonolysis and reactions using KMnO4 have different outcomes depending on whether the reaction involves an alkane or alkene.

Electrophiles and Nucleophiles

• Electrophiles are electron-loving species.
• Nucleophiles are electron-rich species.
• Examples of positively and negatively charged electrophiles and nucleophiles are given (H+, OH-, etc.).

Test your knowledge on hydrocarbons, specifically focusing on aliphatic and aromatic hydrocarbons, as well as alkanes and cycloalkanes. This quiz will cover the characteristics, bond types, and molecular formulas associated with these essential organic compounds.