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DP IB Chemistry: SL

Topic Questions

Home / IB / Chemistry: SL / DP / Topic Questions / 11. Measurements & Data Processes / 11.1 Spectroscopic Identification / Structured Questions: Paper 2


11.1 Spectroscopic Identification

Question 1a

Marks: 1
a)
Zanamivir is an inhibitor used to treat infections caused by the influenza A and B viruses.
Using section 37 of the data booklet, deduce the hydrogen deficiency of Zanamivir.
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    Question 1b

    Marks: 1
    b)
    Determine which of the following molecules has the same IHD and state the IHD value.
    11-1-q1h
    [1]
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      Question 2a

      Marks: 2
      a)
      An alcohol can be prepared by hydrolysing the halogenoalkane C2H5CHBClCH3 with aqueous sodium hydroxide. The infrared spectrum for C2H5CHClCH3  is shown below with the C–Cl bond absorption labelled.
      e3fe76b9-de02-4c9a-a403-ce95f64b0829

      Using section 26 of the data booklet deduce how IR spectroscopy will change as a result of the above reaction.
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        Question 2b

        Marks: 1
        b)
        The mass spectrum of (CH3)2CHCH2OH is shown below.

        10-2
        Deduce which ion is responsible for the peak with the greatest relative intensity.
        [1]
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          Key Concepts
          Fragmentation patterns

          Question 2c

          Marks: 3
          c)
          Alcohol X has the following percentage composition by mass. Carbon = 68.2%, hydrogen = 13.6%, oxygen = 18.2%. The molecular ion peak in the mass spectrum for alcohol X occurs at m/z = 88.

          i)
          Use this information and section 6 of the data booklet to show that the molecular formula for alcohol X is C5H12O. Include your working.
          [2]

          ii)
          When alcohol X is oxidised, a carboxylic acid can be formed. State what information this gives about alcohol X.
          [1]
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            Question 2d

            Marks: 3
            d)
            The mass spectrum of alcohol X has a major peak at m/z = 45.

            i)
            Draw the structure of the species that could give this peak.
            [1]

            ii)
            Alcohol X has a branched chain. Deduce the structural formula and IUPAC name of alcohol X. Justify your answer.
            [2]
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              Key Concepts
              Fragmentation patterns

              Question 3a

              Marks: 2
              a)
              Clenbuterol, shown below, is considered a performance enhancing drug and is believed to increase short term work rate and cardiovascular output.
              11-1-ib-sl-sq-hard-q3a-clenbuterol
              Deduce the functional groups marked x and y and state to which class they belong to.
              [2]
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                Question 3b

                Marks: 2
                b)
                Determine the m/z value of the molecular ion, M+, of clenbuterol. Justify your answer.
                [2]
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                  Question 3c

                  Marks: 5
                  c)
                  Two students, P and Q, were provided with the mass spectrum of an alkane, shown in below. Student P analysed peaks a and b and concluded that the alkane was one of two structures. Student Q analysed peaks a, b and c and was able to identify one possible alkane structure.
                  11-1-ib-sl-sq-hard-q3c

                  i)
                  Deduce which fragments of the alkane correspond to peaks a, b and c
                  [3] 
                  ii)
                  Suggest why the two students obtained different conclusions.
                  [2]
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                    Question 4a

                    Marks: 4
                    a)
                    Four samples containing isomeric alcohols with molecular formula C4H10O, were studied using 1H NMR spectroscopy
                    Draw structural formulas of the alcohols and deduce the number of peaks in the NMR spectrum of each alcohol

                    [4]

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                      Key Concepts
                      How NMR works

                      Question 4b

                      Marks: 2
                      b)
                      Two of the alcohols produce the same number of peaks in an 1H NMR spectrum. Suggest how they may be distinguished, by further spectroscopy analysis.
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                        Key Concepts
                        How NMR works

                        Question 4c

                        Marks: 2
                        c)
                        Compound A can be converted into compound B via an intermediate species.

                        11-1-q4

                        Suggest how you would be able to determine the difference between Compounds A and B by analysis of their 1H NMR spectra.

                        [2]

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                          Key Concepts
                          How NMR works