Lecture_Packet_7_-_Hydrocarbons__5_

Page 1: Hydrocarbons and Organic Compounds

• Organic Compounds: Compounds that contain carbon. Exceptions include:

  • Carbon Oxides: Molecules like CO and CO2.

  • Carbonate Salts: Containing the CO3^2- ion (e.g., CaCO3).

  • Bicarbonate Salts: Containing the HCO3^- ion (e.g., NaHCO3).

  • Cyanide Salts: Containing the CN^- ion (e.g., NaCN).

  • Cyanate Salts: Containing the CNO^- ion (e.g., NaCNO).

• Examples of Organic Molecules:

  • Ethyl Formate: (C3H6O2) contributes to raspberry smell.

  • Lactic Acid: (C3H6O3) found in sour milk and muscles.

  • Acetaminophen: (C8H9O2N) pain reliever (Tylenol).

• Importance in Health and Medicine:

  • Organic chemistry is essential for body reactions, food energy processing, and drug composition.

  • Example of synthesis: Urea synthesized from ammonium cyanate by Friedrich Wohler in 1828.

• Urea Comparison: Urea from urine is identical in properties to synthesized urea.

Page 2: Organic vs. Inorganic Compounds

• Comparison Chart:

  • Inorganic Compounds: Mostly high-melting solids, high boiling/melting points, mainly ionic and covalent bonding, mostly soluble in water, conductive as electrolytes, mostly nonflammable (1,700,000 types).

  • Organic Compounds: Gases, liquids, solids, generally low boiling/melting points, usually covalent bonding, mostly insoluble in water, mostly non-electrolytes, mostly flammable (10,000,000+ types).

• Reason for Organic Compounds Diversity: Carbon forms four covalent bonds, leading to extensive structural possibilities.

Page 3: Carbon Bonding and Versatility

• Bonding Patterns:

  • Carbon can create varying structures:

    • 4 Single Bonds

    • 1 Double Bond + 2 Single Bonds

    • 1 Triple Bond + 1 Single Bond

    • 2 Double Bonds

• Bonding with Nonmetals:

  • Carbon can bond with nonmetals (H, O, N, halogens), influencing structural diversity.

• Skeleton Structures: Complete skeletons by adding hydrogen to satisfy bonding requirements of carbon (4 bonds), nitrogen (3), oxygen/sulfur (2), and halogens (1).

Page 4: Formula Types for Organic Compounds

• Molecular Formula: Indicates types and counts of atoms without structural details.

  • E.g., Methane (CH4), Vinyl Chloride (C2H3Cl), Ethanol (C2H6O), Dimethyl Ether (C2H6O).

• Structural Formula: Illustrates connections and bonds among atoms.

• Isomers:

  • Structural Isomers: Same atoms, different arrangements; exhibit different properties.

  • Example: Ethanol (C2H6O) vs. Dimethyl Ether (C2H6O).

Page 5: Classification of Hydrocarbons

• Hydrocarbons: Composed only of carbon and hydrogen.

  • Subcategories:

    • Aliphatic: Alkanes, Alkenes, Alkynes.

    • Aromatic: Arenes.

• Types of Hydrocarbons:

  • Alkanes: Single bonds only.

  • Alkenes: Contain double bonds.

  • Alkynes: Contain triple bonds.

• Molecular Formulas: Derived from the type of hydrocarbons:

  • Alkanes: CnH2n+2

  • Cycloalkanes/Alkenes: CnH2n

  • Alkynes: CnH2n-2.

Page 6: Alkanes

• Characteristics: Contain single bonds; important biological structures.

• Types:

  • Normal Alkanes: Continuous carbon chain.

  • Branched Alkanes: Carbons form branches off a continuous chain.

  • Structural Examples: Methane (CH4), Ethane (C2H6), Propane (C3H8), Butane (C4H10), etc.

  • Homologous Series: Similar compounds differing in carbon lengths.

  • Haloalkanes: Alkanes where hydrogen is replaced by halogens.

Page 7: Branched Alkanes

• Definition: Carbons not connected in a single line; presence of branches.

• Example: Isobutane (C4H10) vs. Butane (C4H10).

Page 8: Cycloalkanes and Substituted Forms

• Cycloalkanes: Carbons form rings; have unique properties due to their structure.

  • 3 Carbons: Cyclopropane (C3H6)

  • 4 Carbons: Cyclobutane (C4H8).

• Substituted Cycloalkanes: When an atom/group replaces a hydrogen atom.

Page 9: Physical Properties of Alkanes

• Properties:

  1. Nonpolar molecules.

  2. Low boiling points compared to similar size molecules.

  3. Insoluble in water; soluble in nonpolar solvents.

  4. Less dense than water.

Page 10: Physical States of Alkanes

• States:

  • C1-C4: Gases

  • C5-C20: Liquids

  • C21+: Solids

Page 11: Chemical Reactions in Organic Chemistry

• Key Reactions: Combustion and synthesis.

  • Combustion: Flammable, exothermic, crucial for energy extraction.

  • Combustion of Alkanes Examples: Methane (CH4) and Propane (C3H8).

Page 12: Alkenes and Alkynes

• Alkenes: At least one double bond.

• Alkynes: At least one triple bond.

• Bonding and Shape:

  • Different shapes based on bonding patterns influencing molecular properties.

Page 13: Substituted Alkenes and Isomerism

• Substituted Alkenes: Atoms/groups replace hydrogens.

• Geometric Isomers: Different spatial arrangements (cis/trans).

Page 14: Addition Reactions of Alkenes

• Definition: Simple molecules added to alkenes, forming new compounds while breaking double bonds.

Page 15: Aromatic Hydrocarbons (Arenes)

• Definition: Hydrocarbons containing an aromatic ring, starting with Benzene (C6H6).

Page 16: Chemical Properties of Arenes

• Reactivity: Arenes have stable aromatic sextets, leading to substitution reactions.

Page 17: Summary of Hydrocarbon Reactions

• Types of Reactions:

  1. Combustion

  2. Isomerization

  3. Addition

  4. Substitution

Page 18: Additional Problems and Concepts

• Problems assessing structural understanding and predicting boiling points, common reactions, and structural classifications.