QuestionCompound A has the structural formula CH3CH2CH(CH3)CH2OH.
(a) Give the molecular formula of A.
(b) Give the empirical formula of A.
(c) Name the functional group in A and the homologous series it belongs to.
(d) Give the systematic name of A.Answers(a) Count each atom group by group: CH3 (1 C, 3 H), CH2 (1 C, 2 H), CH (1 C, 1 H), CH3 (1 C, 3 H), CH2 (1 C, 2 H) and OH (1 O, 1 H). That is 5 carbon atoms, 12 hydrogen atoms and 1 oxygen atom, so the molecular formula is C5H12O. Check: alcohols are CnH2n+1OH, and n = 5 gives C5H11OH, which is the same.(b) 5, 12 and 1 have no common factor, so the empirical formula is also C5H12O.(c) The -OH group is the hydroxyl group, so A is in the alcohols series.(d) Find the longest chain that contains the carbon bonded to OH. Starting from the CH2OH carbon, the chain runs CH2OH, CH, CH2, CH3: four carbon atoms, so the stem is butan-. Number from the OH end so it gets the lowest number: OH is on C1. The CH3 branch is on C2. The name is 2-methylbutan-1-ol.Common mistakes: counting only 4 carbons because the branch is hidden in brackets, and numbering from the wrong end to give 3-methylbutan-4-ol.
(a) Give the molecular formula of A.
(b) Give the empirical formula of A.
(c) Name the functional group in A and the homologous series it belongs to.
(d) Give the systematic name of A.Answers(a) Count each atom group by group: CH3 (1 C, 3 H), CH2 (1 C, 2 H), CH (1 C, 1 H), CH3 (1 C, 3 H), CH2 (1 C, 2 H) and OH (1 O, 1 H). That is 5 carbon atoms, 12 hydrogen atoms and 1 oxygen atom, so the molecular formula is C5H12O. Check: alcohols are CnH2n+1OH, and n = 5 gives C5H11OH, which is the same.(b) 5, 12 and 1 have no common factor, so the empirical formula is also C5H12O.(c) The -OH group is the hydroxyl group, so A is in the alcohols series.(d) Find the longest chain that contains the carbon bonded to OH. Starting from the CH2OH carbon, the chain runs CH2OH, CH, CH2, CH3: four carbon atoms, so the stem is butan-. Number from the OH end so it gets the lowest number: OH is on C1. The CH3 branch is on C2. The name is 2-methylbutan-1-ol.Common mistakes: counting only 4 carbons because the branch is hidden in brackets, and numbering from the wrong end to give 3-methylbutan-4-ol.