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

Exam code: H032

3 hours42 questions
11 mark

Which molecule is not planar?

  • C2H4

  • C2H6

  • H2CO

  • HCN

21 mark

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

  • Boron

  • Magnesium 

  • Silicon 

  • Sulfur

31 mark

What is the shape around the carbon atoms in graphene?

  • Linear

  • Pyramidal 

  • Tetrahedral 

  • Trigonal planar

41 mark

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

61b0d7c4-0cc6-46ec-b2de-47b1df2626ff

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 °

51 mark

Which molecule is non-polar?

  • SF6

  • H2O

  • PF3

  • NH3

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

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

81 mark

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

  • 107°

  • 120°

  • 180°

  • 109.5°

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°

    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

      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°

      21 mark

      Which molecule is nonpolar?

      • CH3CHICH3  

      • BF3

      • BrF5

      • CH3CHO

      31 mark

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

      • H3O 

      • TlBr32-

      • BCl3

      • NH3

      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

      51 mark

      Which organic compound has the highest boiling point?

      • Butan-1-ol

      • Butane

      • 1-chlorobutane

      • Propane

      61 mark

      Which molecule has the lowest boiling point?

      • CH3CH2CHO

      • CH3CH2CH2Cl

      • CH3CH2CH3

      • CH3CH2COOH

      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 

      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

      91 mark

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

      • Sodium 

      • Diamond

      • Phosphorus 

      • Beryllium 

      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

      111 mark

      Which compound has polar molecules?

      • OCl2

      • BCl3

      • BCl4

      • SCl6

      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

      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

      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?

        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


         

          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

          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