The Shapes of Simple Molecules & Ions (OCR AS Chemistry)

Exam Questions

3 hours42 questions
11 mark

Which molecule is not planar?

  • C2H4

  • C2H6

  • H2CO

  • HCN

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21 mark

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

  • Boron

  • Magnesium 

  • Silicon 

  • Sulfur

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31 mark

What is the shape around the carbon atoms in graphene?

  • Linear

  • Pyramidal 

  • Tetrahedral 

  • Trigonal planar

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41 mark

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

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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 °

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51 mark

Which molecule is non-polar?

  • SF6

  • H2O

  • PF3

  • NH3

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61 mark

Which substance contains hydrogen bonding in the liquid state?

  • CH3(CH2)4CH3

  • CH3(CH2)3CHFCH3

  • CH3(CH2)3COCH3

  • CH3(CH2)3CH(OH)CH3

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71 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

  • Permanent dipole–dipole interactions

  • Induced dipole–dipole interactions

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81 mark

What is the correct bond angle in a trigonal planar molecule?

  • 107°

  • 120°

  • 180°

  • 109.5°

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91 mark

Which of the following is correct?

 

Shape of SF6 molecule

Bond angle in SF6 molecule

A

Octahedral

90°

B

Square planar

90°

C

Trigonal bipyramidal 

120°

D

Tetrahedral 

109.5°

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    101 mark

    Which statement 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

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      11 mark

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

      • Tetrahedral and 109.5°

      • Square planar and 90°

      • V-shaped and 105°

      • Tetrahedral and 107°

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      21 mark

      Which molecule is nonpolar?

      • CH3CHICH3  

      • BF3

      • BrF5

      • CH3CHO

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      31 mark

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

      • H3O+  

      • TlBr32-

      • BCl3

      • NH3

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      41 mark

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

      Serine

      Serine

      • London dispersion forces 

      • Permanent dipole-dipole forces

      • Hydrogen bonding

      • Covalent bonding

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      51 mark

      Which organic compound has the highest boiling point?

      • Butan-1-ol

      • Butane

      • 1-chlorobutane

      • Propane

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      61 mark

      Which molecule has the lowest boiling point?

      • CH3CH2CHO

      • CH3CH2CH2Cl

      • CH3CH2CH3

      • CH3CH2COOH

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      71 mark

      Which statement explains why water is 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 

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      81 mark

      Which statement explains why hexane has 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

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      91 mark

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

      • Sodium 

      • Diamond

      • Phosphorus 

      • Beryllium 

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      101 mark

      Four atoms, 1–4, are labelled in the structure below.

      8c9c9c72-3e53-4e7a-9de5-2be89db440e8

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

      • Atom 1

      • Atom 2

      • Atom 3

      • Atom 4

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      111 mark

      Which compound has polar molecules?

      • OCl2

      • BCl3

      • BCl4

      • SCl6

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      121 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

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      11 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

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      21 mark

      Four atoms, 1-4, are labelled in the structure below

      aspirin---identify-the-atom2

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

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        31 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

         

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          41 mark

          Which of the following statements 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

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          51 mark

          This question is about butane, propanone and the amino acid glycine (R group -H).

          Which of the following statements 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

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