1) The family of organic compounds with functional groups that do not consist only of hydrocarbons is A) aldehydes. B) alkanes. C) alkenes. D) alkynes. E) aromatics. 2) Two or more compounds with the same molecular formula but with the atoms connected differently are referred to as A) normal alkanes. B) branched alkanes. C) functional groups. D) constitutional isomers. E) conformations. 3) In straight-chain alkanes, the carbon atoms on each end of the molecule always form bonds with ________ atoms of hydrogen; the carbons within the molecule always form bonds with ________ hydrogen atoms.