Syllabus Edition

First teaching 2023

First exams 2025

|

The Covalent Model (HL IB Chemistry)

Exam Questions

10 hours149 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

  • coordinate bond

  • ionic bond

  • hydrogen bond

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21 mark

Silver and iodine are both shiny crystalline solids.

Which forces exist between neighbouring 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

London dispersion forces

metallic

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    31 mark

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

    Using the following key:

     bold times   N electron

    cross times   H electron

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

    q6_4-1_easy_mcq_ib-chemistry-sl

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      41 mark

      Which of these atoms is most electronegative?

      • Cl

      • Mg

      • Br

      • Na

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      51 mark

      Based on 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

      1.9

      C

      magnesium

      1.3

      D

      potassium

      0.8

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        61 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?

        ma1_14-2_ib_sl_mcq_easy

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          71 mark

          Two boron-containing species, boron trifluoride (BF3) and the borohydride ion (BH4-), 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

            Graphite has a structure containing layers of carbon atoms in hexagonal rings.

            Why is graphite a good conductor of electricity?

            • It has delocalised ions which can move and carry charge

            • It has delocalised electrons which are mobile

            • There are only weak London forces between the layers

            • Each carbon atom in the layers has only three covalent bonds

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            91 mark

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

            • 107°

            • 120°

            • 180°

            • 109.5°

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            101 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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              111 mark

              Which statement about the physical properties of substances is correct?

              • Covalent structures always have high melting points

              • Metals only conduct electricity when solid

              • Metals always have high melting points 

              • Ionic substances conduct electricity when liquid 

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              121 mark

              Which of the following statements about graphite is correct?

              • The bond angle in graphite is 109.5 o

              • There are only London forces between the layers of graphite

              • Graphite has a higher melting point than diamond

              • Graphite is soluble in water

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              131 mark

              Which of the following is correct?

               

              Shape of CCl4 molecule

              Bond angle in CCl4 molecule

              A

              Octahedral

              90°

              B

              Square planar

              90°

              C

              Trigonal bipyramidal

              120°

              D

              Tetrahedral

              109.5°

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                141 mark

                Which substance is described in the table below?

                Melting point

                Electrical Conductivity

                Solubility

                Very high

                Non-conductor

                Does not dissolve

                • Silicon dioxide

                • Buckminsterfullerene

                • Graphite

                • Sodium chloride 

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                151 mark

                Which of the following is the correct resonance hybrid structure of the carbonate ion, CO32-?

                q8_14-2_ib_sl_easy_mcq

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                  161 mark

                  Which of the following dipole labels are not correct?q1_4-3_ib_sl_easy_mcq

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                    171 mark

                    Which of the following compounds is polar?

                    • CCl4

                    • BF3

                    • PH3

                    • CH3CH3

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                    181 mark

                    Which of the following statements is not correct?

                    • The strongest type of intermolecular force in ammonia is hydrogen bonding

                    • The strongest type of intermolecular force in water is hydrogen bonding

                    • The strongest type of intermolecular force in hydrogen chloride is permanent dipole 

                    • The strongest type of intermolecular forces in ethanol is permanent dipole 

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                    191 mark

                    Which of the following statements about ethylamine, CH3CH2NH2, is correct?

                    • The strongest type of intermolecular force are London dispersion forces

                    • The nitrogen atom does not have a lone pair present

                    • The strongest type of intermolecular force is permanent dipole permanent dipole forces

                    • The strongest type of intermolecular force is hydrogen bonding

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                    201 mark

                    Which of the following statements about butane, CH3CH2CH2CH3, and propanone, CH3COCH3 are correct? 

                    1. The boiling point of propanone is higher than butane
                    2. The boiling point of butane is higher than propanone
                    3. The strongest type of intermolecular force in propanone are permanent dipole permanent dipole forces
                    • I and II only

                    • I and III only

                    • II and III only

                    • I, II and III

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                    21
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                    1 mark

                    Which of the following can form a sigma (σ) bond?

                    I.   Overlap between an s-orbital and a p-orbital

                    II.  Overlap between two s-orbitals

                    III. Overlap between two p-orbitals

                    • I only

                    • I and II only

                    • II and III only

                    • I, II and III

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                    22
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                    1 mark

                    What is the correct number of sigma (σ) and pi (π) bonds in ethanoic anhydride, CH3COOCOCH3?

                    ethanoic-anhydride-ib-hl-mcq-14-1-e-q2

                      Number of sigma (σ) bonds Number of pi (π) bonds
                    A. 10 4
                    B. 10 2
                    C. 12 2
                    D. 12 4

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                      23
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                      1 mark

                      Which element does not form stable compounds that break the octet rule?

                      • Sulfur

                      • Oxygen

                      • Boron

                      • Chlorine

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                      24
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                      1 mark

                      What are the bond angles in a molecule with five electron domains, XY5?

                        Axial bond angles / o Equatorial bond angles / o
                      A. 90 90
                      B. 120 90
                      C. 90 120
                      D. 120 120

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                        25
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                        1 mark

                        What is the correct formula to work out the formal charge on an atom?

                        • FC = (Number of valence electrons) - 1 half(Number of bonding electrons) - (Number of non-bonding electrons)

                        • FC = (Number of valence electrons) - (Number of bonding electrons) - (Number of non-bonding electrons)

                        • FC = (Number of valence electrons) - (Number of non-bonding electrons) - (Number of bonding electrons)

                        • FC = (Number of valence electrons) - 1 half(Number of non-bonding electrons) - (Number of bonding electrons)

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                        26
                        Sme Calculator
                        1 mark

                        Which compound contains delocalised electrons?

                        • Cyclohexane, C6H12

                        • Cyclohexene, C6H10

                        • Benzene, C6H6

                        • Cyclohexanol, C6H11OH

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                        27
                        Sme Calculator
                        1 mark

                        Which structure does not show resonance?

                        • Carbonate ion, CO32-

                        • Hydroxide ion, OH-

                        • Ethanoate ion, CH3COO-

                        • Nitrate ion, NO3-

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                        28
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                        1 mark

                        Which is the correct description of how an sp2 orbital is formed?

                        • One s-orbital mixes with three p-orbitals

                        • Two s-orbitals mixes with two p-orbitals

                        • One s-orbital mixes with two p-orbitals

                        • One s-orbital mixes with one p-orbital

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                        29
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                        1 mark

                        The structure of glycine is shown below:

                        glycine-structure-ib-hl-mcq-14-2-e-q5

                        What is the correct number of sp2 and sp3 hybridized atoms in glycine?

                          Number of sp2 hybridised atoms Number of sp3 hybridised atoms
                        A. 8 2
                        B. 2 8
                        C. 3 2
                        D. 2 3

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                          11 mark

                          Which of the following statements about 2-methylpropan-2-ol, CH3C(CH3)(OH)CH3, are correct ? 

                          1. The structure contains 16 bonding pair of electrons
                          2. The O-C-C bond angle is 109.5 o
                          3. The total number of electrons is 32
                          • I and II only 

                          • I and III only 

                          • II and III only 

                          • I, II and III

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                          21 mark

                          Which of the following molecules has the biggest overall dipole?

                          q2_4-1_medium_mcq_ib-chemistry-hl

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                            31 mark

                             The electronegativity of four elements are given below 

                            N = 3.0       H = 2.1       F = 4.0      P = 2.1      

                             What is the correct order of polarity for the following compounds

                            • PH3 < PF3 < NF3 < NH3

                            • PH3 < PF3 < NH3 < NF3   

                            • NF3 < NH3 < PH3 < PF3 

                            • PH3 < NH3 < NF3 < PF3 

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                            41 mark

                            Below are four molecules. Which is the most polar molecule present?

                            • CH3NH2

                            • CH4

                            • CCl4

                            • CO2

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                            51 mark

                            The correct order of increasing boiling points for the following compounds is

                            • 1-chlorobutane < butane < butan-1-ol 

                            • Butan-1-ol < 1-chlorobutane < butane, 

                            • Butane < 1-chlorobutane < butan-1-ol 

                            • Butan-1-ol < butane < 1-chlorobutane 

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                            61 mark

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

                            Otne2dIl_q3_4-3_ib_sl_medium_mcq

                            • London dispersion forces

                            • Permanent dipole permanent dipole forces

                            • Hydrogen bonding

                            • Covalent bonding 

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                            71 mark

                            Hexane, C6H14 and 2,2-dimethylbutane, CH3C(CH3)2CH2CH3, are two isomers of one another and have the same Mr of 86.0. 

                            Hexane has a higher boiling point than 2,2-dimethylbutane. 

                            Which of the following statements is not correct?

                            • hexane has a higher boiling point because it is a straight chain molecule

                            • 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 permanent dipole forces

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                            81 mark

                            Which of the following statements about propanal and propanone are correct?

                            q6_4-3_ib_sl_medium_mcq

                            1. The strongest type of intermolecular force in both molecules is hydrogen bonding
                            2. The strongest type of intermolecular force in both molecules is permanent dipole permanent dipole forces
                            3. Both compounds are soluble in water

                            • I and II only

                            • I and III only

                            • II and III only

                            • I, II and III

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                            91 mark

                            Which molecule has the lowest boiling point?

                            • CH3CH2CHO

                            • CH3CH2CH2Cl

                            • CH3CH2CH3

                            • CH3CH2COOH

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                            101 mark

                            Which of the following statements about ammonia, NH3, is not correct?

                            • The lone pair on nitrogen can form a coordinate bond

                            • The bond angle in the NH3 molecule is 107o

                            • The strongest type of intermolecular force is hydrogen bonding 

                            • There are four bonding pairs of electrons in the NH3 molecule

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                            111 mark

                            The following equation shows the dissociation equilibrium of PCl5

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

                            The percentage yield of PCl3 varies with temperature. 

                            At 160°C PCl3 yield is 13% and at 300°C yield is100%. 

                            Which of the following rows is correct?

                             

                            The reaction is

                            Shape of PCl3 molecule

                            A

                            exothermic

                            trigonal pyramidal

                            B

                            exothermic

                            trigonal planar

                            C

                            endothermic

                            trigonal pyramidal

                            D

                            endothermic

                            trigonal planar

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                              121 mark

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

                              How may this reaction be written using 3D structures to show  the shapes of the reactants and products?q2-1_14-2_ib_sl_medium_mcq

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                              131 mark

                              Which of the following statements about graphite are correct? 

                              1.    The carbon atoms are joined together by three covalent bonds
                              2.    Graphite contains delocalised electrons
                              3.    The C-C-C bond angle is 109.5o
                              • I and II only

                              • I and III only

                              • II and III only

                              • I, II and III

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                              141 mark

                              Which statement below shows the correct information about diamond and silicon?

                              • Diamond is macromolecular and silicon is simple molecular

                              • The bond angles in the two structures are the same

                              • The bond lengths are longer in C-C than in Si-Si

                              • Diamond and silicon both conduct electricity due to delocalised electrons in their structure

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                              151 mark

                              How many lone pairs of electrons are there around the chlorine atom in a molecule of chlorine trifluoride, ClF3?

                              • 1

                              • 2

                              • 3

                              • 0

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                              161 mark

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

                              • H3O+  

                              • TlBr32-

                              • BCl3

                              • NH3 

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                              171 mark

                              Which of the following statements about silicon dioxide is correct? 

                              1.    Silicon dioxide forms a giant covalent network
                              2.    Each silicon atom is covalently bonded to four oxygen atoms
                              3.    Silicon dioxide molecules are V-shaped
                              • I and II only

                              • I and III only

                              • II and III only

                              • I, II and III

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                              181 mark

                              Ibuprofen is an anti-inflammatory drug that is used for treating pain, fever and inflammation. The structure is shown below.q8_4-2_ib_sl_medium_mcq 

                              Ibuprofen

                               What are the correct bond angles for a and b?

                               

                              a

                              b

                              A

                              120o

                              120o

                              B

                              107o

                              109.5o

                              C

                              109.5o

                              120o

                              D

                              120o

                              109.5o

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                                191 mark

                                Which of the following molecules obeys the octet rule?

                                • BF3

                                • HCN

                                • BeCl2

                                • CS2

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                                201 mark

                                Which row in the table is correct?

                                 

                                Shape of diamond structure

                                Melting point of buckminsterfullerene

                                Bond angle in graphene

                                A

                                Square planar

                                Relatively high

                                90o

                                B

                                Tetrahedral

                                Relatively low

                                107o

                                C

                                Trigonal Planar

                                Relatively high

                                109.5o

                                D

                                Tetrahedral

                                Relatively low

                                120o

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                                  211 mark

                                  Dichlorodifluoromethane, CCl2F2, has been used in aerosol propellants and as a refrigerant.

                                  Which statement helps to explain why dichlorodifluoromethane is chemically inert?

                                   

                                  • the carbon-fluorine bond energy is large

                                  • the carbon-fluorine bond has a low polarity

                                  • fluorine is highly electronegative

                                  • fluorine compounds are non-flammable

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                                  221 mark

                                  Which of the following statements are true for XeO3?

                                  1. Has a trigonal pyramidal shape
                                  2. One possible Lewis structure has two oxygen atoms with a formal charge of -1
                                  3. Xenon has a formal charge of +2 in one possible Lewis structure
                                  • I and II only

                                  • I and III only  

                                  • II and III only 

                                  • I, II and III

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                                  231 mark

                                  Which species breaks the octet rule?

                                  • PCl3

                                  • BF4-

                                  • SCl4

                                  • NH4+

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                                  241 mark

                                  Which molecule is trigonal bipyramidal in shape?

                                  • PCl3

                                  • SiCl4

                                  • PCl5

                                  • SF6

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                                  251 mark

                                  How many sigma (σ) and pi (π) bonds are there in the following molecule?

                                  q4_14-1_ib_hl_mcq

                                   

                                  Sigma (σ) bonds

                                  Pi (π) bonds

                                  A

                                  9

                                  2

                                  B

                                  9

                                  4

                                  C

                                  11

                                  2

                                  D

                                  11

                                  4

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                                    261 mark

                                    Which combination correctly describes the geometry of BrF4- ?

                                     

                                    Electron domain geometry around Br

                                    Molecular geometry around Br

                                    A

                                    Octahedral

                                    Tetrahedral

                                    B

                                    Tetrahedral

                                    Square planar

                                    C

                                    Octahedral

                                    Square planar

                                    D

                                    Tetrahedral

                                    Tetrahedral

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                                      271 mark

                                      Which species contain delocalised electrons?

                                      q1_14-2_ib_hl_medium_mcq

                                      • I and II only

                                      • I and III only

                                      • II and III only 

                                      • I, II and III

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                                      281 mark

                                      Which combination describes the PH4+ ion?

                                       

                                      Molecular geometry

                                      Central atom hybridisation

                                      A

                                      Tetrahedral

                                      sp3

                                      B

                                      Square planar

                                      sp3

                                      C

                                      Tetrahedral

                                      sp2

                                      D

                                      Square planar

                                      sp2

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                                        291 mark

                                        What is the hybridisation of carbon and oxygen in methanol?

                                        q4_14-2_ib_hl_medium_mcq

                                         

                                        Hybridisation of C

                                        Hybridisation of O

                                        A

                                        sp2

                                        sp2

                                        B

                                        sp2

                                        sp

                                        C

                                        sp

                                        sp2

                                        D

                                        sp3

                                        sp3

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                                          301 mark

                                          Which species have delocalised π electrons? 

                                          1.   CH3COCH3
                                          2.   NO2-
                                          3.   CO32-
                                          • I and II only 

                                          • I and III only 

                                          • II and III only

                                          • I, II and III

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                                          11 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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                                            21 mark

                                            What is the correct structure of the chlorite ion, ClO2- ?q3-4-1_hard_mcq_ib-chemistry-sl

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                                              31 mark

                                              Which of the following statements about 2-chloropropene, CH2C(Cl)CH3 is correct?

                                              • There are 4 lone pairs in the molecule

                                              • There are 22 valence electrons in the molecule 

                                              • All the atoms in the molecule follow the octet rule

                                              • There are 7 σ bonds

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                                              41 mark

                                              Which of the following structures do not obey the octet rule?

                                              1. BeCl2
                                              2. BF3
                                              3. H2O
                                              • I and II only

                                              • I and III only

                                              • II and III only

                                              • I, II and III

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                                              51 mark

                                              Which is the shortest bond length in the following gases?

                                              • oxygen-oxygen in oxygen gas, O2

                                              • carbon-carbon in ethyne gas, C2H2

                                              • nitrogen-nitrogen in nitrogen gas, N2

                                              • oxygen-oxygen in ozone gas, O3

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                                              61 mark

                                              Which statement best describes the intramolecular bonding in a carbonate ion, CO32-?

                                              • Only London forces

                                              • Electrostatic attraction between pairs of electrons and positively charged nuclei

                                              • Permanent dipole permanent dipole forces

                                              • Electrostatic attraction between separate carbonate ions

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                                              71 mark

                                              The number of electrons in the valence shell of elements X and Y are 5 and 7 respectively. What is the formula and type of compound formed from these elements?

                                              • Covalent, XY3

                                              • Ionic, XY3

                                              • Covalent, X3Y

                                              • Ionic, X3Y

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                                              81 mark

                                              The nitrate(V) ion, NO3-, is a polyatomic ion, bonded by covalent bonds.

                                              Which of the following shows the correct displayed formula for the nitrate ion?

                                              q9-4-1_hard_mcq_ib-chemistry-sl

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                                                91 mark

                                                In which series of compounds does covalent character increase when going from left to right?

                                                • KI, KBr, KCl

                                                • NaI, KI, RbI

                                                • NaCl, MgCl2, AlCl3

                                                • SO2, P4O10, SiO2

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                                                101 mark

                                                Which of the following molecules will have the highest boiling point?

                                                • CH3CH2CHO

                                                • CH3CH2CH2NH2

                                                • CH3CH2OCH3

                                                • CH3CH2CH2F

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                                                111 mark

                                                What is the correct order of boiling points for the following molecules, from lowest to highest?

                                                • CH3F < F2 < CH3CH2F < HF

                                                • F2 < CH3F < CH3CH2F < HF

                                                • F2 < CH3CH2F < CH3F < HF

                                                • HF < CH3CH2F <C H3F < F2  

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                                                121 mark

                                                In which of the following processes do hydrogen bonds get broken?

                                                • 2HBr (g) → H2 (g) + Br2 (g)

                                                • C2H6 (l) → 2C (g) + 6H (g)

                                                • H2 (l) → H2 (g)

                                                • NH3 (l) → NH3 (g) 

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                                                131 mark

                                                Hydrogen bonding occurs between molecules of propanal, CH3CH2CHO, and molecules of liquid Y. Which of the following is most likely to be liquid Y?

                                                • CH3CO2CH3

                                                • CH3OH

                                                • CH3COCH3

                                                • CH3CHO

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                                                141 mark

                                                The following statements are all correct. Which of the statements can be explained, in part, by hydrogen bonding?

                                                1. Ice is less dense than water
                                                2. Butanone has a lower boiling point than butan-1-ol
                                                3. At room temperature butanone can mix with water
                                                • I and II only

                                                • I and III only

                                                • II and III only

                                                • I, II and III

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                                                151 mark

                                                Hydrogen bonding can occur between propanal, CH3CH2CHO and which other molecule?

                                                • CH3COOH

                                                • CH3CO2CH3

                                                • CH3CH2F

                                                • CH3COCH3

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                                                161 mark

                                                Which of the following about dimethylamine, NH(CH3)2 , is correct?

                                                 

                                                Bond angle

                                                Strongest type of intermolecular force present

                                                A

                                                109.5

                                                Permanent dipole permanent dipole forces

                                                B

                                                109.5

                                                London dispersion forces

                                                C

                                                107o

                                                Hydrogen bonding

                                                D

                                                105o

                                                Hydrogen bonding

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                                                  171 mark

                                                  Which of the following statements are correct? 

                                                  1. The strongest type of intermolecular force between BF3 molecules are permanent dipole permanent dipole forces
                                                  2. The strongest type of intermolecular force between HCN molecules are permanent dipole permanent dipole forces
                                                  3. The bond angle in HCN is larger than the bond angle in BF3
                                                  • I and II only

                                                  • I and III only

                                                  • II and III only

                                                  • I, II and III

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                                                  181 mark

                                                  Which of the species shown below does not have resonance structures?

                                                  • C6H6

                                                  • CO32-

                                                  • C2H4

                                                  • O3

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                                                  191 mark

                                                  The correct molecular geometry and domain geometry for phosphorus trichloride, PCl3, is:

                                                   

                                                  molecular geometry

                                                  domain geometry

                                                  A

                                                  trigonal planar

                                                  trigonal planar

                                                  B

                                                  trigonal pyramid

                                                  tetrahedral

                                                  C

                                                  tetrahedral

                                                  trigonal planar

                                                  D

                                                  tetrahedral

                                                  trigonal pyramid

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                                                    201 mark

                                                    Below are statements about the structure and bonding in silicon dioxide. Which pair of statements is correct?

                                                     

                                                    structure

                                                    bonding

                                                    A

                                                    silicon dioxide molecules are bent linear

                                                    silicon atoms have covalent bonds to two oxygen atoms

                                                    B

                                                    silicon dioxide has a giant macromolecular structure

                                                    each oxygen bonds covalently to one silicon atom

                                                    C

                                                    silicon dioxide has a giant macromolecular structure

                                                    silicon atoms bond to four oxygen atoms

                                                    D

                                                    silicon dioxide molecules are linear

                                                    silicon and oxygen atoms are joined by a double covalent bond

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                                                      211 mark

                                                      Which compounds have an ionic lattice structure in the solid state?

                                                      1.   silicon dioxide
                                                      2.   sodium iodide
                                                      3.   ammonium sulfate
                                                      • I and II only

                                                      • I and III only

                                                      • II and III only

                                                      • I, II and III

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                                                      221 mark

                                                      What is the correct shape of a ClF2- ion?

                                                      • Linear

                                                      • T-Shaped

                                                      • Bent

                                                      • Trigonal planar

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                                                      231 mark

                                                      The correct shape and bond angle for the TlBr32- ion?

                                                       

                                                      Shape

                                                      Bond angle

                                                      A

                                                      Pyramidal

                                                      120°

                                                      B

                                                      Pyramidal

                                                      107°

                                                      C

                                                      Tetrahedral

                                                      109.5°

                                                      D

                                                      Tetrahedral

                                                      120°

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                                                        241 mark

                                                        Which of the following is correct for the molecules of BeCl2 and BeCl42-?

                                                         

                                                        BeCl2

                                                        BeCl42-

                                                         

                                                        Shape

                                                        Bond angle

                                                        Shape

                                                        Bond angle

                                                        A

                                                        Linear

                                                        109.5°

                                                        Square planar

                                                        90°

                                                        B

                                                        V-shaped

                                                        107°

                                                        Square planar

                                                        90°

                                                        C

                                                        V-shaped

                                                        105°

                                                        Tetrahedral

                                                        109.5°

                                                        D

                                                        Linear

                                                        180°

                                                        Tetrahedral

                                                        109.5°

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                                                          251 mark

                                                          Tramadol is an example of a painkiller which is classed as an opioid analgesic. It binds to opioid receptors in the central nervous system and inhibits noradrenaline and serotonin reuptake inhibiting pain transmission 

                                                          The structure is shown below 

                                                          Which of the following are the correct bond angles for a, b and c?

                                                          q8_4-2_ib_sl_hard_mcq

                                                           

                                                          a

                                                          b

                                                          c

                                                          A

                                                          120o

                                                          109.5o

                                                          107o

                                                          B

                                                          120o

                                                          107o

                                                          105o

                                                          C

                                                          107o

                                                          109.5o

                                                          107o

                                                          D

                                                          109.5o

                                                          107o

                                                          105o

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                                                            261 mark

                                                            Some properties of substance X are given in the following table 

                                                            Melting Point

                                                            Very high

                                                            Strength

                                                            Very strong across the layer

                                                            Conductivity

                                                            Excellent conductor

                                                            Example of a Use

                                                            Used as a coating for smartphones, tablets and computers

                                                            What is a possible identity of substance X?

                                                            • Graphene

                                                            • Graphite

                                                            • Silicon dioxide 

                                                            • Buckminsterfullerene

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                                                            271 mark

                                                            Sulfur forms the compound S4N4 with nitrogen, the structure is shown below.q10_4-2_ib_sl_hard_mcq

                                                              Which of the following statements about S4N4 is correct?

                                                            • The sulfur atom marked x has two lone pairs

                                                            • The sulfur atom marked y has two lone pairs

                                                            • Each N atom has two lone pairs 

                                                            • The N-S-N bond angle will be larger than S=N=S bond angle 

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                                                            281 mark

                                                            Nitrous acid is produced when nitrogen dioxide dissolves in water to produce acid rain. What is the correct Lewis structure for nitrous acid?

                                                            q3-8-3-mcq-hard-ib-chemistry-sl

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                                                              29
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                                                              1 mark

                                                              The structure of benzoic acid is shown below:

                                                              benzoic-acid-structure-ib-hl-mcq-14-1-h-q1

                                                              What is the correct number of sigma (σ) bonds and pi (π) electrons in benzoic acid?

                                                                Number of sigma bonds Number of pi electrons
                                                              A. 10 6
                                                              B. 15 8
                                                              C. 17 4
                                                              D. 9 10

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                                                                30
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                                                                1 mark

                                                                Which of the following correctly describes the F-S-F bond angles in sulfur tetrafluoride, SF4?

                                                                  Axial F-S-F bond angle / ° Equatorial F-S-F bond angle / °
                                                                A. 90 120
                                                                B. <90 >120
                                                                C.  <90 <120
                                                                D. >90 <120

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                                                                  31
                                                                  Sme Calculator
                                                                  1 mark

                                                                  Which of the following species is polar?

                                                                  • ICl4-

                                                                  • PF5

                                                                  • SO3

                                                                  • SH2

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                                                                  32
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                                                                  1 mark

                                                                  What are the formal charges on the atoms labelled 1, 2 and 3 on the hydrogen phosphate ion, HPO42-?

                                                                  -6Ym9orR_hydrogen-phosphate-structure-ib-hl-mcq-14-1-h-q4

                                                                    Formal charge on atom 1 Formal charge on atom 2 Formal charge on atom 3
                                                                  A. 0 0 -1
                                                                  B. 0 +1 -1
                                                                  C. -1 0 -1
                                                                  D. +1 -2 0

                                                                   

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                                                                    33
                                                                    Sme Calculator
                                                                    1 mark

                                                                    The structure of the DNA base cytosine is shown below:

                                                                    cytosine-structure-ib-hl-mcq-14-1-h-q5

                                                                    What is the correct number of sp3 and sp2 orbitals in a cytosine molecule?

                                                                      Number of sp3 orbitals  Number of sp2 orbitals
                                                                    A. 2 6
                                                                    B. 12 12
                                                                    C. 9 15
                                                                    D. 8 18

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                                                                      34
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                                                                      1 mark

                                                                      Which species can be represented with only one Lewis structure?

                                                                      • H2PO4-

                                                                      • O3

                                                                      • CH3COCH3

                                                                      • 1,3 cyclohexadiene

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                                                                      35
                                                                      Sme Calculator
                                                                      1 mark

                                                                      In which group do both compounds contain delocalised electrons?

                                                                      • K2CO3 and cyclohexene, C6H10

                                                                      • KOH and methybenzene, C7H8

                                                                      • KHCO3 and buta-1,3-diene, C4H6

                                                                      • Methanol and sodium methanoate, HCOONa

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                                                                      36
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                                                                      1 mark

                                                                      Which is not a correct statement about sp3 hybridised carbons?

                                                                      • They can form sigma or pi bonds

                                                                      • They have the electron arrangement 1s22s12p3

                                                                      • They have four bonding orbitals of equal energy

                                                                      • The bonding orbitals have bevelled 1 fourth s character and bevelled 3 over 4 p character

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                                                                      37
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                                                                      1 mark

                                                                      The structure of the painkiller paracetamol, often known as acetaminophen, is shown below:

                                                                      paracetamol-structure-ib-hl-mcq-14-2-h-q5

                                                                      Which of the following is not present in the structure?

                                                                      • 5 lone pairs

                                                                      • 7 atoms with bond angles of 120o around them

                                                                      • 8 atoms with sp2 hybrid orbitals

                                                                      • 16 sigma (σ) bonds

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                                                                      381 mark

                                                                      The structure of benzene is often shown as

                                                                      10-1-h-q7i-mcqs-ib-chemistry

                                                                      This is a representation of a resonance hybrid structure that lies between these two possible structures

                                                                      10-1-h-q7ii-mcqs-ib-chemistry

                                                                      Evidence for this resonance structure is:

                                                                      1. The carbon-carbon bond lengths lie between the value for a single and a double bond
                                                                      2. The bond angles are all equal in benzene
                                                                      3. The enthalpy of hydrogenation of benzene is less exothermic than expected
                                                                      • I and II only

                                                                      • I and III only

                                                                      • II and III only

                                                                      • I, II and III

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                                                                      391 mark

                                                                      Which row of the table is correct about the trend and explanation in the boiling points of the alcohols CH3OH, C2H5OH and C3H7OH?



                                                                                  

                                                                                   Trend in boiling points                    

                                                                                                             Explanation                                                      

                                                                          A

                                                                      CH3OH >C2H5OH > C3H7OH 

                                                                      The London dispersion forces decrease with each additional CH2

                                                                      B

                                                                      CH3OH >C2H5OH > C3H7OH 

                                                                      The strength of the hydrogen bonds decreases with each additional CH2

                                                                      C

                                                                      C3H7OH >C2H5OH >CH3OH   

                                                                      The London dispersion forces increase with each additional CH2

                                                                      D

                                                                      C3H7OH >C2H5OH >CH3OH  

                                                                      The strength of the hydrogen bonds increases with each additional CH2

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