Unit 4 (Nomenclature and Newman Projections)

This video covers the IUPAC rules for naming cycloalkanes, which are cyclic hydrocarbons. It explains how to name simple cycloalkanes like cyclopropane, cyclobutane, and cyclohexane, and how to handle substituents on these rings. The video also discusses how to choose the parent chain when a cycloalkane is attached to a longer carbon chain and provides examples with halogen and alcohol substituents.

This video focuses on the naming of bicyclic cycloalkanes, which are formed by two fused rings. It introduces the concept of bridgeheads and bridges, explains how to number the molecule according to the longest bridges, and walks through a naming example using the IUPAC system. The video also highlights the importance of the correct numbering to give substituents the lowest possible numbers.

This video covers the IUPAC naming rules for alkenes, alkynes, and cycloalkenes. It explains how the presence of double and triple bonds changes the naming of hydrocarbons, and how to prioritize the numbering of molecules based on the position of the double bond or substituents. The video also covers how to name cyclic alkenes and alkyne compounds​.

In this video, we explore trends in hydrocarbons, particularly how their physical properties like boiling point, melting point, and solubility vary with molecular size and structure. It discusses how branching and ring structure in alkanes, cycloalkanes, and alkyl halides influence their boiling points and solubility, emphasizing how hydrocarbons behave as nonpolar solvents​​.

This video introduces Newman projections as a tool to visualize the 3D orientation of substituents on single-bonded carbons. It demonstrates how to draw Newman projections for molecules like 2,3-dibromo-2,3-dimethylpentane, explaining how to rotate around a bond and correctly assign positions to substituents. The video emphasizes the importance of properly interpreting wedges and dashes in bond-line structures when converting to Newman projections​​​.

In this video, we explore the different conformations of cyclohexane, emphasizing the chair conformation as the most stable due to minimal strain. The video also introduces less stable conformations like the boat, half-chair, and twist-boat forms, explaining how the chair conformation predominates in solution because it has the lowest potential energy​​​.

In this video, we discuss ring strain in cyclic molecules, which results from deviations in bond angles and torsional strain. The video explains how these strains contribute to the instability of cyclic molecules like cyclopropane and cyclobutane, compared to more stable cyclohexane. It also touches on steric hindrance in aliphatic molecules, which occurs when large substituents block other interactions​.

This video introduces the concept of degrees of unsaturation (IHD), also known as the index of hydrogen deficiency. It explains how to calculate the IHD by comparing a molecule’s hydrogen count to that of its saturated alkane counterpart, accounting for double bonds, triple bonds, and rings. The video also provides a formula for IHD calculation and walks through examples with ethene, ethyne, and cyclohexane​.