Without looking at the structures, give molecular formulas for the compounds: (a) 4-(1,1-dimethylethyl)octane and (b) 5-(1,2,2-trimethylpropyl)nonane. Use the names of the groups to determine the number of carbon atoms; then use the (2n + 2) rule.

IUPAC nomenclature is a systematic method of naming organic chemical compounds as recommended by the International Union of Pure and Applied Chemistry (IUPAC). It provides a standardized way to describe the structure of a compound using specific rules, which include identifying the longest carbon chain, numbering the chain, and naming substituents.

Alkyl groups are groups of carbon and hydrogen atoms arranged in a chain, derived from alkanes by removing one hydrogen atom. They are named based on the number of carbon atoms they contain, such as methyl (CH3), ethyl (C2H5), and propyl (C3H7). Understanding alkyl groups is crucial for determining the structure and molecular formula of complex organic compounds.

The molecular formula of an alkane can be determined using the general formula CnH2n+2, where n is the number of carbon atoms. This formula accounts for the saturated nature of alkanes, which have single bonds between carbon atoms. By identifying the number of carbon atoms in the main chain and substituents, one can calculate the total number of hydrogen atoms to derive the molecular formula.