SOLVED

21) Choose the INCORRECT statement. A) In thermal cracking large hydrocarbon molecules are broken down into smaller molecules, ideally, molecules in the gasoline range. B) Reforming converts straight-chain hydrocarbons into branched-chain hydrocarbons. C) Branched-chain hydrocarbons have higher octane numbers. D) Alkylation is the joining of small hydrocarbon fragments to larger molecules. E) Engine knocking is caused by the smooth firing of gasoline. 22) Define “conformation”. A) Conformations are different arrangements of bonds in space B) Conformations are different structural representations of the same molecule. C) Conformations are different spatial arrangements one structure can have D) Conformations are two enantiomers. E) Conformations are all possible structural isomers for a given molecular formula 23) What are skew conformations? A) Skew conformations all possible conformations between the eclipsed and staggered extremes. B) Skew conformations in which linear molecules get twisted. C) Skew conformations are conformations that have the greatest energy D) Skew conformations are conformations that have the lowest energy E) Skew conformations are conformations that have the greatest energy barrier 24) Which of the following methods are used for the laboratory alkane synthesis? I) catalytic addition of hydrogen to multiple carbon – carbon bonds II) catalytic hydrogenation of aldehydes III) from halogenated hydrocarbons and sodium IV) from alkali metal salts of organic acids and alkali metal hydroxides V) dehydrohalogenation of organic halogen compounds A) I), II), and V) B) II), III), and V) C) I), III), and IV) D) II), III), and IV) E) III), IV) and V) 25) Reforming is: A) a process that joins low molecular mass hydrocarbons into higher molecular mass hydrocarbons B) a process that converts straight chain hydrocarbons to branched hydrocarbons C) a process that converts unsaturated organic compounds to saturated ones D) a process that breaks down high molecular mass hydrocarbons into low molecular mass hydrocarbons E) a process that converts branched hydrocarbons to straight chain hydrocarbons 26) Which of the following five positions would result in the most stable molecule for a large group like t-butyl, -C(CH3)3? A) equatorial position in boat cyclohexane B) axial position in boat cyclohexane C) two or more of these answers are equally stable D) axial position in chair cyclohexane E) equatorial position in chair cyclohexane 27) Choose the INCORRECT statement. A) Axial H atoms are directed above and below the cyclohexane ring. B) A substitution reaction typically involves a functional group replacing a hydrogen atom on a chain or ring containing molecule. C) A free radical is a compound with an unpaired electron. D) LPG is linear polymerized gas. E) Unsaturated usually means a double, triple or delocalized electron system is present in the molecule. 28) Which of the following represent two different chair forms of methylcyclohexane? A) B) C) D) E) 29) Find the answer that has correct both the two structures of cis-1-isopropyl-4-methylcyclohexane and their relative stability (stability is indicated with “>” meaning “more stable than”). A) B) C) D) 30) Which of the following structures represent the structure of trans-1-bromo-2-methylcyclohexane? A) B) C) D) E)