A LevelChemistryOCRExam Questions2. Foundations in ChemistryThe Shapes of Simple Molecules & Ions

The Shapes of Simple Molecules & Ions (OCR A Level Chemistry A): Exam Questions

Exam code: H432

3 hours44 questions

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The Shapes of Simple Molecules & Ions

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Hard
1
1 mark

Which molecule is not planar?

  • C2H4

  • C2H6

  • H2CO

  • HCN

Choose your answer

2
1 mark

Which element has induced dipole–dipole interactions (London forces) in its solid lattice?

  • Boron

  • Magnesium 

  • Silicon 

  • Sulfur

Choose your answer

3
1 mark

What is the shape around the carbon atoms in graphene?

  • Linear

  • Pyramidal 

  • Tetrahedral 

  • Trigonal planar

Choose your answer

4
1 mark

A ‘dot-and-cross’ diagram for nitrogen trichloride, NCl3, is shown below.

Dot-and-cross diagram for nitrogen trichloride.

Which row shows the correct shape and bond angle in a molecule of NCl3?

 

Name of shape

Bond angle 

A

Pyramidal

104.5 °

B

Pyramidal

107 °

C

Tetrahedral

107 °

D

Trigonal planar

120 °

    Choose your answer

    5
    1 mark

    Which molecule is non-polar?

    • SF6

    • H2O

    • PF3

    • NH3

    Choose your answer

    6
    1 mark

    Which substance contains hydrogen bonding in the liquid state?

    • CH3(CH2)4CH3

    • CH3(CH2)3CHFCH3

    • CH3(CH2)3COCH3

    • CH3(CH2)3CH(OH)CH3

    Choose your answer

    7
    1 mark

    The boiling point of hydrogen bromide is –67 °C.

    The boiling point of hydrogen iodide is –34 °C.

    The different boiling points can be explained in terms of the strength of bonds or interactions.

    Which bonds or interactions are responsible for the higher boiling point of hydrogen iodide?

    • Covalent bonds

    • Hydrogen bonds

    • Induced dipole–dipole interactions

    • Permanent dipole–dipole interactions

    Choose your answer

    8
    1 mark

    What is the bond angle in a trigonal planar molecule?

    • 107°

    • 120°

    • 180°

    • 109.5°

    Choose your answer

    9
    1 mark

    Which row is correct for an SF6 molecule?

    Shape

    Bond angle

    A

    Octahedral

    90°

    B

    Square planar

    90°

    C

    Trigonal bipyramidal

    120°

    D

    Tetrahedral

    109.5°

      Choose your answer

      10
      1 mark

      Which row is correct for a molecule of CCl4?

      Total number of valence electrons

      Number of bonding pairs

      Number of lone pairs

      A

      30

      4

      2

      B

      32

      4

      0

      C

      34

      4

      1

      D

      16

      4

      0

        Choose your answer

        11
        1 mark

        What is the shape and bond angle of a molecule of hydrogen sulfide, H2S?

        • Linear, 180o

        • Non-linear, 104.5o

        • Tetrahedral, 109.5o

        • Trigonal planar, 120o

        Choose your answer

        1
        1 mark

        What is the shape and bond angle of the phosphonium ion, PH4+? 

        • Tetrahedral and 109.5°

        • Square planar and 90°

        • V-shaped and 105°

        • Tetrahedral and 107°

        Choose your answer

        2
        1 mark

        Which molecule is nonpolar?

        • CH3CHICH3  

        • BF3

        • BrF5

        • CH3CHO

        Choose your answer

        3
        1 mark

        Which one of these species has a bond angle of 120°?

        • H3O+  

        • TlBr32-

        • BCl3

        • NH3

        Choose your answer

        4
        1 mark

        What is the strongest type of intermolecular force in the amino acid molecule serine?

        Chemical structure of serine, an amino acid, showing its molecular formula with hydroxyl, amine, and carboxyl groups.

        • London dispersion forces 

        • Permanent dipole-dipole forces

        • Hydrogen bonding

        • Covalent bonding

        Choose your answer

        5
        1 mark

        Which organic compound has the highest boiling point?

        • Butan-1-ol

        • Butane

        • 1-chlorobutane

        • Propane

        Choose your answer

        6
        1 mark

        Which molecule has the lowest boiling point?

        • CH3CH2CHO

        • CH3CH2CH2Cl

        • CH3CH2CH3

        • CH3CH2COOH

        Choose your answer

        7
        1 mark

        Why is water more dense than ice?

        • Ice contains hydrogen bonds, but water does not contain hydrogen bonds

        • Hydrogen bonds are stronger in water than in ice

        • Hydrogen bonds hold H2O molecules closer together in water 

        • Ice is a solid and water is a liquid 

        Choose your answer

        8
        1 mark

        Why does hexane have a higher boiling point than 2,2-dimethylbutane?

        • Hexane has a higher Mr than 2,2-dimethylbutane

        • 2,2-dimethylbutane has a lower boiling point as it is a branched molecule 

        • 2,2-dimethylbutane only contains London dispersion forces 

        • Hexane contains permanent dipole dipole forces

        Choose your answer

        9
        1 mark

        Which element has induced dipole dipole interactions (London dispersion forces) in its solid lattice?

        • Sodium 

        • Diamond

        • Phosphorus 

        • Beryllium 

        Choose your answer

        10
        1 mark

        Four atoms, A-D, are labelled in the structure of alanine below.

        Chemical structure of alanine with the CH3 group labelled A, a CH group labelled B, a carboxylic carbon labelled C, and the NH2 group labelled D.

        Which atom has a trigonal planar arrangement of bonds around it?

          Choose your answer

          11
          1 mark

          Which compound has polar molecules?

          • OCl2

          • BCl3

          • BCl4

          • SCl6

          Choose your answer

          12
          1 mark

          The boiling point of butan-1-ol is 118 °C. The boiling point of 2-methylpropan-2-ol is 82 °C.

          Why is the boiling point of butan-1-ol higher than that of 2-methylpropan-2-ol?

          • Butan-1-ol has stronger induced dipole–dipole interactions because it has more electrons

          • Butan-1-ol has stronger induced dipole–dipole interactions because it has a straight-chain structure

          • Butan-1-ol can form hydrogen bonds while 2-methylpropan-2-ol cannot

          • Butan-1-ol is more stable because it is a primary alcohol

          Choose your answer

          13
          1 mark

          Which statement correctly explains the trend in the boiling points of the halogens from chlorine to iodine?

          • The boiling point increases because the permanent dipole-dipole interactions become stronger as the molecules become more polar.

          • The boiling point increases because the number of electrons increases, leading to stronger London (induced dipole-dipole) forces.

          • The boiling point decreases because the covalent bond strength decreases as the atomic radius increases.

          • The boiling point decreases because the shielding effect increases, weakening the attraction between molecules.

          Choose your answer

          1
          1 mark

          Which compound has non-polar molecules?

          • E-1,2-dichlorobut-2-ene

          • E-2,3-dichlorobut-2-ene

          • Z-2,3-dichlorobut-2-ene

          • Z-1,4-dichlorobut-2-ene

          Choose your answer

          2
          1 mark

          Four atoms, A-D, are labelled in the structure below

          Chemical structure of benzene-1,2-dicarboxylic acid, with four atoms labelled A, B, C and D

          Which atom has a v-shaped arrangement of bonds around it?

            Choose your answer

            3
            1 mark

            Which row has the correct shape, bond angle and explanation for the following molecules?

            Molecule

            Shape

            Bond angle

            Explanation

            A

            Ethanoic acid

            Pyramidal around the carbonyl carbon

            107o

            The carbon atom is sp2 hybridised so the double bond repels more than the single bonds

            B

            [Cu(NH3)4(H2O)2]2+

            Octahedral

            90o

            The eight bonding pairs will repel each other equally

            C

            Cisplatin

            Square planar

            109.5o

            Minimises the repulsion between the electrons in the d orbitals

            * D*

            Sulfur dioxide

            Bent

            119o

            Lone pairs repel more than bonding pairs due to a higher concentration of the electron charge cloud

              Choose your answer

              4
              1 mark

              Which statement(s) is/are correct?

              1. Bromoethane is more reactive than chloroethane because bromine is less electronegative than chlorine.

              2. The C-Br bond in bromoethane requires more energy to break than the C-Cl bond in chloroethane due to the C-Br bond being more polar.

              3. The C-Br bond in bromoethane is stronger than the C-Cl bond in chloroethane due to bromine having an increased nuclear charge.

              • 1, 2 and 3

              • Only 1 and 2

              • Only 2 and 3

              • Only 1

              Choose your answer

              5
              1 mark

              Which statement(s) is/are correct?

              1. Butane and propanone have the same number of electrons so their induced dipole-dipole intermolecular forces are the same.

              2. Only glycine will dissolve in water because it has hydrogen bonding.

              3. Within a protein, glycine has one place in which a hydrogen bond could form.

              • 1, 2 and 3

              • Only 1 and 2

              • Only 2 and 3

              • Only 1

              Choose your answer