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DP IB Chemistry: SL

Topic Questions

Home / IB / Chemistry: SL / DP / Topic Questions / 4. Chemical Bonding & Structure / 4.2 Resonance, Shapes & Giant Structures / Structured Questions: Paper 2


4.2 Resonance, Shapes & Giant Structures

Question 1a

Marks: 2
a)
A simple amide is HCONH2.
Draw the Lewis (electron dot) structure for this molecule.
[2]
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    Question 1b

    Marks: 6
    b)
    Predict and explain the bond angle around the C and N atoms.
    [6]
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      Question 1c

      Marks: 4
      c)
      Predict the molecular geometry and the electron domain geometry around the C and N in HCONH2.
      [4]
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        Question 1d

        Marks: 3
        d)
        State, with a reason, whether HCONH2 is a polar molecule.
        [3]
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          Question 2a

          Marks: 2
          a)
          Tetrafluoroethene, C2F4, and tetrafluorohydrazine, N2F4, are fluorides of adjacent elements in the Periodic Table.
          Draw the Lewis (electron dot) structures for C2F4 and N2F4 showing all valance electrons.
          [2]
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            Question 2b

            Marks: 5
            b)
            Predict and explain the F-C-F bond angle in tetrafluoroethene and the F-N-F bond angle in tetrafluorohydrazine.
            [5]
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              Question 2c

              Marks: 4
              c)
              Tetrafluorohydrazine is a polar molecule but tetrafluoroethene is not.
              Explain the difference in molecular polarity.
              [4]
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                Question 3a

                Marks: 3
                a)
                Draw the Lewis (electron dot) structure of the carbonate ion, CO32-.
                [3]
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                  Key Concepts
                  Lewis structures

                  Question 3b

                  Marks: 3
                  b)
                  Deduce the number of possible resonance structures for the carbonate ion, CO32-, and draw two of them.
                  [3]
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                    Key Concepts
                    Resonance structures

                    Question 3c

                    Marks: 3
                    c)
                    Discuss how the bonding in the carbonate ion, CO32-, evidences the presence of the resonance structures.
                    [3]
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                      Key Concepts
                      Resonance structures

                      Question 3d

                      Marks: 2
                      d)
                      Organic molecules can also show resonance. The methanoate ion, HCOO-, shows similar resonance forms to the carbonate ion, CO32-.
                      The corresponding organic acid, methanoic acid, also has resonance structures.

                      4-2-ib-sl-sq-hard-q3d-methanoic-acid-structure

                      Draw another resonance structure of methanoic acid.
                      [2]
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                        Key Concepts
                        Resonance structures

                        Question 4a

                        Marks: 2
                        a)
                        Some of the physical and structural properties of diamond and graphite are shown below:
                         
                        Property Diamond Graphite
                        Melting Point at 1 atmosphere / K 4200 4300
                        Density / g cm-3 3.51 2.26
                        Average bond length / nm 0.155 0.142
                        Delocalisation No Yes
                        Hybridisation sp3 sp2
                        Electron mobility cm2 V-1 s-1 1000 - 2000 15000 - 200000

                        Suggest why the melting point of graphite is higher than that of diamond, using the information in the table.

                        [2]

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                          Question 4b

                          Marks: 2
                          b)
                          Predict the bond order in both diamond and graphite.
                          [2]
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                            Question 4c

                            Marks: 2
                            c)
                            Graphene has the structure of a single layer of graphite. 
                            Suggest, giving a reason, the electron mobility of graphene compared to graphite.
                            [2]
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                              Question 4d

                              Marks: 6
                              d)
                              Graphite is a layered giant structure, containing London dispersion forces between the layers, whereas diamond has covalent bonds across all planes.
                              Describe and explain, based on structure and bonding, the differences expected when each of graphite and diamond are moved across a paper surface.
                              [6]
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