Syllabus Edition

First teaching 2020

Last exams 2024

|

Chemical Bonding (CIE AS Chemistry)

Exam Questions

3 hours45 questions
11 mark

Phosphine, PH3, can react with a hydrogen ion, H+, to form the phosphonium ion.

Which type of bond is formed in this reaction?

  • Dipole-dipole forces

  • Dative covalent bond

  • Ionic bond

  • Hydrogen bond

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21 mark

Silver and iodine are both shiny crystalline solids. 

Which forces exist between neighboring iodine molecules in solid iodine and particles in solid silver?

 

Iodine

Silver

A

Metallic bonds

Covalent bonds

B

Ionic bonds

Metallic

C

Covalent bonds

Covalent bonds

D

Van der Waals’ forces

Metallic

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    31 mark

    Below are four solids. Which of these contains more than one kind of bonding?

    • Diamond

    • Sodium chloride

    • Iron

    • Ice

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    41 mark

    Hydrazine, N2H4, is a precursor for multiple pharmaceutical compounds.

    Which of the diagrams below illustrate the most likely structure and bond angle of hydrazine?

    •   1-3-e-4a

    • 1-3-e-4b

    • 1-3-e-4c

    • 1-3-e-4d

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    51 mark

    Which of the following dipole labels are not correct?

    • 1-3-e-5a

    • 1-3-e-5b

    • 1-3-e-5c

    • 1-3-e-5d

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    61 mark

    In acidic conditions, ammonia, NH3, reacts with a proton, H+, to form ammonium NH4+

    Using the following key:

         N electron

     bold cross times   H electron

    Which of the following Dot & Cross diagrams correctly illustrate electron movement in this reaction?

    • 1-3-e-6a

    • 1-3-e-6b

    • 1-3-e-6c

    • 1-3-e-6d

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    71 mark

    Two boron-containing components, boron trifluoride (BF3) and sodium borohydride (NaBH4), have different molecular shapes. 

    What are the shapes around the boron atom in these molecules?

     

    Boron trifluoride (BF3)

    Borohydride ion (BH4)

    A

    Pyramidal

    Tetrahedral

    B

    Pyramidal

    Square planar

    C

    Trigonal planar

    Tetrahedral

    D

    Trigonal planar

    Square planar

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      81 mark

      Which of these atoms is most electronegative?

      • Cl

      • Mg

      • Br

      • Na

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      91 mark

      Which of the following compounds is not bonded ionically?

      • CaCO3

      • CH3OH

      • NaOH

      • BaCl2

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      101 mark

      “Electrostatic attraction between cations and delocalised electrons” 

      Which of the following bonds does the statement best describe?

      • Hydrogen

      • Ionic

      • Dipole

      • Metallic

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      111 mark

      Which of the following materials only contain one type of bond in solid form?

      • Ammonium chloride 

      • Brass (an alloy of zinc and copper)

      • Ice

      • Iodine crystals

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      121 mark

      Which statement correctly describes what happens when silicon tetrachloride is added to water?

      • The SiCl4 reacts to give an acidic solution only

      • The SiCl4 reacts to give a precipitate and an acidic solution

      • The SiCl4 reacts to give a precipitate and a neutral solution

      • The SiCl4 dissolves to give a neutral solution only

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      11 mark

      The following equation shows the dissociation equilibrium of PCl5.

      PCl5 (g)  →  PCl3 (g)  + Cl2 (g)

      The percentage yield of PCl3 differs with temperature. 

      At 160°C PCl3 yield is 13% and at 300°C yield is 100%. 

       

      The reaction is 

      Shape of PCl3 molecule

      A

      Exothermic

      Pyramidal

      B

      Exothermic

      Trigonal planar

      C

      Endothermic

      Pyramidal

      D

      Endothermic

      Trigonal planar

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        21 mark

        N2 is a covalently bonded molecule that makes up 78% of gas in the air we breathe.

        Which of the following is not present in an N2 molecule?

        • Two lone pairs of electrons

        • Three shared pairs of electrons

        • Three π bonds

        • 180° bond angle

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        31 mark

        Using your knowledge of trends in electronegativity, deduce which of the following elements has electronegativity most similar to beryllium?

        • Boron

        • Aluminium

        • Silicon

        • Indium

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        41 mark

        Three lone pairs of electrons can be found around the central atom of which of the following ions?

        • PF6

        • ClF2

        • BF2

        • SF5

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        51 mark

        Which diagrams correctly illustrate the formation of a σ bond and a π bond from the overlap of electron orbitals?

        1-3-m-5

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          61 mark

          Which of the following changes of state shows only dispersion Van der Waals’ forces being overcome?

          • C3H6 (l) rightwards arrow C3H6 (s)

          • CO2 (l) rightwards arrow CO2 (g)

          • H2O (s) rightwards arrow H2O (l)

          • C2H5OH (l) rightwards arrow C2H5OH (g)

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          71 mark

          Before the 1820s scientists believed that inorganic and organic molecules were fundamentally different and could not be interchanged, the experiment by Francis Wőhler changed this theory as he was able to produce organic urea, CO(NH2)2 from inorganic ammonium cyanate.

          What is the formula of the cyanate ion in ammonium cyanate?

          • CO-

          • NO-

          • CNO-

          • CNO2-

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          81 mark

          “The bond ....X…. between the hydrogen and halide in HBr is ….Y…. than in Hl.”

          Which pair of words does not correctly complete the sentence above.

           

          Y

          A

          Length

          Shorter

          B

          Energy

          Greater

          C

          Angle

          Smaller

          D

          Polarity

          Greater

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            91 mark

            Which of the following molecules has the biggest overall dipole?

            • 1-3-m-9a

            • 1-3-m-9b

            • 1-3-m-9c

            • 1-3-m-9d

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            11 mark

            1.00g of propanone is reacted with 5.00g of ethane-1,2-diol and the strong acid benzene sulphonic acid, C6H5SO3H. The mixture is heated under reflux in an inert solvent.

            1-3-h-1

            Which of the following statements is not correct?

            • Propanone has a higher melting point than ethane-1,2-diol

            • Both products are polar molecules

            • Ethane-1,2-diol is soluble in water

            • Water has a higher melting point than liquid Y

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            21 mark

            Hydrogen bonding occurs between molecules of liquid methanal, HCHO, and molecules of liquid Y. Which of the following is most likely to be liquid Y?

            • CH3CO2CH3

            • CH3OH

            • CH3COCH3

            • CH3CHO

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            31 mark

            A student is studying conversions of different species. The two conversions below show similarities. 

            PCl5 → PCl6

            C2H4 → C2H6

            What similar features do these two conversions have?

            • Decrease in bond angle of the species involved

            • Disappearance of a π bond

            • Change in oxidation state of an element

            • A lone pair of electrons in the product

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            41 mark

            Equal amounts of 1-chloroethane, 1-bromoethane and 1-iodoethane were added to separate test-tubes each containing 2.0 cm3 of aqueous silver nitrate. The test tubes were heated and a cloudy precipitate formed in each tube. 

            The equation below, within which X represents a halogen atom, and R represents CH3CH2, describes the hydrolysis reaction occurring within the test tubes.

            1-3-h-4The rate of AgX production, as measured by the speed of precipitation formation, was in the order AgI > AgBr > AgCl.

            Why is this?

            • The first ionisation energy of the halogen decreases from Cl to I

            • The solubility of AgX(s) decreases from AgCl to AgI

            • The bond energy of R–X decreases from RCl to RI

            • The R–X bond polarity decreases from RCl to RI

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            51 mark

            Concerning their Pauling electronegativity values, which atom is more likely to form a covalent bond with fluorine?

             

            Atom

            Pauling value

             

            Fluorine

            4.0

            A

            Hydrogen

            2.2

            B

            Copper

            1.95

            C

            Magnesium

            1.3

            D

            Potassium

            0.82

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              61 mark

              Boron trifluoride, BF3, reacts with Trimethylamine, (CH3)3N, to form a compound of formula (CH3)3N.BF3.

              How may this reaction be written in terms of the shapes of the reactants and products?

              • 1-3-h-6a

              • 1-3-h-6b

              • 1-3-h-6d

              • 1-3-h-6c

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              71 mark

              CHCl3 and Br2 are both liquids at room temperature due to the existence of dipoles.

              What dipoles are involved within CHCl3 and Br2

               

              CHCl3

              Br2

              A

              Induced dipoles only

              Induced dipoles only

              B

              Induced dipoles only

              Induced dipoles and permanent dipoles

              C

              Induced dipoles and permanent dipoles

              Induced dipoles and permanent dipoles

              D

              Induced dipoles and permanent dipoles

              Induced dipoles only

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                81 mark

                Calcium Oxide, CaO2, can be used in toothpaste as a teeth whitener. It is formed when calcium metal burns in oxygen. Which dot-and-cross diagram correctly illustrates the electron structure of the peroxide ion in CaO2.

                1-3-diagram-q8h

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                  91 mark

                  Bones contain a molecule called hydroxyapatite, Ca(OH)2.3Ca3(PO4)2, which functions as a strengthening agent. 

                  As you age, calcium ions can be lost from hydroxyapatite, causing the bones to weaken. Strontium salt tablets can be taken to strengthen bones as the strontium ions replace the calcium ions lost from hydroxyapatite

                  Which of these is a correct statement?

                  • Strontium hydroxide is less soluble than calcium hydroxide and so will precipitate better in the bone structure.

                  • There is ionic, covalent and metallic bonding in hydroxyapatite which gives it strength.

                  • Strontium ions are nearly the same size as calcium ions and so may easily replace them in the hydroxyapatite.

                  • Strontium forms a covalent bond with phosphate.

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