The Covalent Model (DP IB Chemistry: SL): Exam Questions

5 hours80 questions
11 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

    21 mark

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

    Which diagram correctly shows the Lewis structures of the reactants and product?

    bold times N electron

    cross times H electron

    q6_4-1_easy_mcq_ib-chemistry-sl
      31 mark

      Which of these atoms is most electronegative?

      • Cl

      • Mg

      • Br

      • Na

      41 mark

      Fluorine has a Pauling electronegativity value of 4.0.

      Which of the following atoms is most likely to form a covalent bond with fluorine based on electronegativity values?

      • Hydrogen (2.2)

      • Copper (1.9)

      • Magnesium (1.3)

      • Potassium (0.8)

      51 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?

      • Structural formula of hydrazine showing two nitrogen atoms bonded with a 120-degree angle. Each nitrogen is bonded to two hydrogen atoms.

      • Structural formula of hydrazine showing two nitrogen atoms bonded with a 109.5-degree angle. Each nitrogen is bonded to two hydrogen atoms.

      • Structural formula of hydrazine showing two nitrogen atoms bonded with a 107-degree angle. Each nitrogen is bonded to two hydrogen atoms.

      • Structural formula of hydrazine showing two nitrogen atoms bonded with a 107-degree angle. Each nitrogen is bonded to two hydrogen atoms.

      61 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

        71 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

        81 mark

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

        • 107°

        • 120°

        • 180°

        • 109.5°

        91 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 

        101 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

        111 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°

          121 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 

          131 mark

          Which of the following dipole labels are not correct?

          • Propanol:

            (δ+) C-O (δ-)

          • Propanal:

            (δ+) C=O (δ-)

          • Propane:

            (δ+) C-H (δ-)

          • Chloropropane:

            (δ+) C-Cl (δ-)

          141 mark

          Which of the following compounds is polar?

          • CCl4

          • BF3

          • PH3

          • CH3CH3

          151 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 a dipole–dipole force

          • The strongest type of intermolecular forces in ethanol is a dipole–dipole force

          161 mark

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

          • The strongest type of intermolecular force is London dispersion forces

          • The nitrogen atom does not have a lone pair

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

          • The strongest type of intermolecular force is hydrogen bonding

          171 mark

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

          I. Butane has a higher boiling point than propanone.

          II. The strongest type of intermolecular force in propanone is dipole–dipole forces.

          III. Butane has only London dispersion forces between its molecules.

          • I and II only

          • I and III only

          • II and III only

          • I, II and III

          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?

          • coordinate bond

          • ionic bond

          • non-polar covalent bond

          • polar covalent bond

          21 mark

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

          I.The structure contains 16 bonding pair of electrons

          II.The O-C-C bond angle is 109.5 o

          III. The total number of electrons is 32

          • I and II only 

          • I and III only 

          • II and III only 

          • I, II and III

          31 mark

          Which of the following molecules is the most polar?

          • CH3NH2

          • CH4

          • CCl4

          • CO2

          41 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 

          51 mark

          What is the strongest type of intermolecular force between serine molecules?

          Chemical structure of serine, showing carbon, hydrogen, nitrogen, and oxygen bonds. Key elements include amino and hydroxyl groups.
          • London dispersion forces

          • Dipole-dipole forces

          • Hydrogen bonding

          • Ion-dipole forces

          61 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

          71 mark

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

          q6_4-3_ib_sl_medium_mcq

          I. Both compounds exhibit dipole–dipole forces between their molecules.

          II. Both compounds can form hydrogen bonds with water.

          III. Propanone has a higher boiling point than propanal.

          • I and II only

          • I and III only

          • II and III only

          • I, II and III

          81 mark

          Which molecule has the lowest boiling point?

          • CH3CH2CHO

          • CH3CH2CH2Cl

          • CH3CH2CH3

          • CH3CH2COOH

          91 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

          101 mark

          The following equation shows the dissociation equilibrium of PCl5

          PCl5 (g) ⇌ PCl3 (g) + Cl2 (g) 

          The percentage yield of PCl3 is 13% at 160°C and increases to 97% at 300°C. 

          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

            111 mark

            Which of the following statements about graphite are correct? 

            I.   The carbon atoms are joined together by three covalent bonds

            II.   Graphite contains delocalised electrons

            III.   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

            121 mark

            Which statement about diamond and silicon is correct?

            • Diamond has a covalent network structure and silicon is a simple molecule

            • 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

            131 mark

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

            • H3O+  

            • TlBr32-

            • BCl3

            • NH3 

            141 mark

            Which of the following statements about silicon dioxide is correct? 

            I.   Silicon dioxide forms a giant covalent network

            II.  Each silicon atom is covalently bonded to four oxygen atoms

            III.  Silicon dioxide molecules are V-shaped

            • I and II only

            • I and III only

            • II and III only

            • I, II and III

            151 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

              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

              161 mark

              In which molecule do all atoms, other than hydrogen, have a complete octet?

              • BF3

              • HCN

              • BeCl2

              • CS2

              171 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

                181 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

                11 mark

                What are the main types of intermolecular forces that exist between molecules of trichloromethane, CHCl3, and between molecules of bromine, Br2?


                CHCl3

                Br2

                A

                London dispersion forces only

                London dispersion forces only

                B

                London dispersion forces only

                London dispersion forces and permanent dipole-dipole interactions

                C

                London dispersion forces and permanent dipole-dipole interactions

                London dispersion forces and permanent dipole-dipole interactions

                D

                London dispersion forces and permanent dipole-dipole interactions

                London dispersion forces only

                  21 mark

                  Which of the following species have a central atom that does not have a complete octet?

                  I.BeCl2

                  II.BF3

                  IICCl4

                  • I and II only

                  • I and III only

                  • II and III only

                  • I, II and III

                  31 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

                  41 mark

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

                  • CH3CH2CHO

                  • CH3CH2CH2NH2

                  • CH3CH2OCH3

                  • CH3CH2CH2F

                  51 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  

                  61 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) 

                  71 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

                  81 mark

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

                  I.Ice is less dense than water

                  II.Butanone has a lower boiling point than butan-1-ol

                  III. At room temperature butanone can mix with water

                  • I and II only

                  • I and III only

                  • II and III only

                  • I, II and III

                  91 mark

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

                  • CH3COOH

                  • CH3CO2CH3

                  • CH3CH2F

                  • CH3COCH3

                  101 mark

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

                   

                  Bond angle

                  Strongest type of intermolecular force present

                  A

                  107

                  Dipole-dipole forces

                  B

                  109.5

                  London dispersion forces

                  C

                  107o

                  Hydrogen bonding

                  D

                  105o

                  Hydrogen bonding

                    111 mark

                    Which of the following statements are correct? 

                    I.The strongest type of intermolecular force between BF3 molecules are permanent dipole permanent dipole forces

                    II.The strongest type of intermolecular force between HCN molecules are permanent dipole permanent dipole forces

                    III. 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

                    121 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

                      131 mark

                      Which row correctly describes the structure and bonding in silicon dioxide?

                       

                      Structure

                      Bonding

                      A

                      Simple molecular

                      Each silicon atom is bonded to two oxygen atoms

                      B

                      Covalent network structure

                      Each oxygen atom is bonded to one silicon atom

                      C

                      Covalent network structure

                      Each silicon atom is bonded to four oxygen atoms

                      D

                      Simple molecular

                      Silicon and oxygen atoms are joined by Si=O double bonds

                        141 mark

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

                        I. silicon dioxide

                        II. sodium iodide

                        III.  ammonium sulfate

                        • I and II only

                        • I and III only

                        • II and III only

                        • I, II and III

                        151 mark

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

                         

                        BeCl2 shape

                        BeCl2 bond angle

                        BeCl42- shape

                        BeCl42- bond angle

                        A

                        Linear

                        180°

                        Square planar

                        90°

                        B

                        V-shaped

                        107°

                        Square planar

                        90°

                        C

                        V-shaped

                        105°

                        Tetrahedral

                        109.5°

                        D

                        Linear

                        180°

                        Tetrahedral

                        109.5°

                          161 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 of tramadol is shown below.

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

                          Chemical structure diagram featuring a hexagonal carbon ring with OH, amine group, and methoxy group labelled a, b, and c respectively.

                           

                          a

                          b

                          c

                          A

                          107o

                          109.5o

                          107o

                          B

                          109.5o

                          107o

                          105o

                          C

                          120o

                          109.5o

                          107o

                          D

                          120o

                          107o

                          105o

                            171 mark

                            A substance has a very high melting point, excellent electrical conductivity, and contains strong covalent bonds within a single layer of atoms.

                            Which substance is most likely to match these properties?

                            • Graphene

                            • Graphite

                            • Silicon dioxide 

                            • Buckminsterfullerene

                            181 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
                              191 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