14.3 - Past Paper Questions

1. What is the best description of the Carbon-Oxygen bond lengths in CO₃^2–?

A. One short and two long bonds

B. One long and two short bonds

C. Three bonds of the same length

D. Three bonds of different lengths

2. What is the number of sigma (s) and pi (p) bonds and the hybridisation of the Carbon atom in

3. Which of the following contain a bond angle of 90^°?

I. PC1₄⁺

II. PCl₅

III. PCl₆^–

A. I and II only

B. I and III only

C. II and III only

D. I, II and III

4. Which allotropes contain Carbon atoms with sp² hybridization?

I. Diamond

II. Graphite

III. C60 Fullerene

A. I and II only

B. I and III only

C. II and III only

D. I, II and III

5. What is the molecular shape and the hybridization of the Nitrogen atom in NH₃?

6. Which statement about sigma and pi bonds is correct?

A. Sigma bonds are formed only by s orbitals and pi bonds are formed only by p orbitals.

B. Sigma bonds are formed only by p orbitals and pi bonds are formed only by s orbitals.

C. Sigma bonds are formed by either s or p orbitals, pi bonds are formed only by p orbitals.

D. Sigma and pi bonds are formed by either s or p orbitals.

7. Consider the following statements.

I. All Carbon-Oxygen bond lengths are equal in CO₃^2–.

II. All Carbon-Oxygen bond lengths are equal in CH₃COOH.

III. All Carbon-Oxygen bond lengths are equal in CH₃COO^–.

Which statements are correct?

A. I and II only

B. I and III only

C. II and III only

D. I, II and III

8. Which statement is correct about multiple bonding between Carbon atoms?

A. Double bonds are formed by two π bonds.

B. Double bonds are weaker than single bonds.

C. π bonds are formed by overlap between s orbitals.

D. π bonds are weaker than sigma bonds.

9. Which particles can act as ligands in complex ion formation?

I. C1^–

II. NH₃

III. H₂O

A. I and II only

B. I and III only

C. II and III only

D. I, II and III

10. Which statements correctly describe the NO₂^– ion?

I. It can be represented by resonance structures.

II. It has two lone pairs of electrons on the N atom.

III. The N atom is sp² hybridized.

A. I and II only

B. I and III only

C. II and III only

D. I, II and III

11. Which is the smallest bond angle in the PF₅ molecule?

A. 90^°

B. 109.5^°

C. 120^°

D. 180^°

12. Which types of hybridization are shown by the Carbon atoms in the compound CH₂ = CH-CH₃?

I. sp

II. sp²

III. sp³

A. I and II only

B. I and III only

C. II and III only

D. I, II and III

13. Identify the types of hybridization shown by the Carbon atoms in the molecule

CH₃CH₂CH₂COOH

I. sp

II. sp²

III. sp³

A. I and II only

B. I and III only

C. II and III only

D. I, II and III

14. Which molecule is square planar in shape?

A. XeO₄

B. XeF₄

C. SF₄

D. SiF₄

15. What is the hybridization of Nitrogen atoms I, II, III and IV in the following molecules?

16. What is the molecular geometry and the Cl–I–Cl bond angle in the ICl₄^– ion?

A. Square planar 90^°

B. Square pyramidal 90^°

C. Tetrahedral 109^°

D. Trigonal pyramidal 107^°

17. What is the geometry of the bonds around an atom with sp² hybridization?

A. 2 bonds at 180^°

B. 3 bonds at 120^°

C. 2 bonds at 90^°, 1 bond at 180^°

D. 4 bonds at 109^°

18. How many sigma (σ) and pi (π) bonds are present in the structure of HCN?

19. How many lone pairs and bonding pairs of electrons surround Xenon in the XeF₄ molecule?

20. (a) Explain the meaning of the term hybridisation.

....................................................................................................................................

(1)

(b) State the type of hybridisation shown by the Carbon atom in the H–C≡N molecule, and the number of s and p bonds present in the C≡N bond.

....................................................................................................................................

(2)

(c) Describe how s and p bonds form.

....................................................................................................................................

(4)

(Total 7 marks)

21. (i) Draw the Lewis structures for Carbon Monoxide, Carbon Dioxide and the Carbonate ion.

.....................................................................................................................................

(3)

(ii) Identify the species with the longest Carbon-Oxygen bond and explain your answer.

.....................................................................................................................................

(3)

(Total 6 marks)

22. In 1954 Linus Pauling was awarded the Chemistry Nobel Prize for his work on the nature of the chemical bond. Covalent bonds are one example of intramolecular bonding.

Explain the formation of the following.

(i) σ bonding

………………………………………………………………………………………

(2)

(ii) π bonding

………………………………………………………………………………………

(2)

(iii) double bonds

………………………………………………………………………………………

(1)

(iv) triple bonds

………………………………………………………………………………………

(1)

(Total 6 marks)

23. Atomic orbitals can mix by hybridisation to form new orbitals for bonding.

Identify the type of hybridisation present in each of the three following molecules.

Deduce and explain their shapes.

(i) OF₂

………………………………………………………………………………………

(3)

(ii) H₂CO

………………………………………………………………………………………

(3)

(iii) C₂H₂

………………………………………………………………………………………

(3)

(Total 9 marks)

24. For the following compounds

PCl₃, PCl₅, POCl₃

(i) Draw a Lewis structure for each molecule in the gas phase.

(Show all non-bonding electron pairs.)

.....................................................................................................................................

(3)

(ii) State the shape of each molecule and predict the bond angles.

.....................................................................................................................................

(6)

(iii) Deduce whether or not each molecule is polar, giving a reason for your answer.

.....................................................................................................................................

(3)

(Total 12 marks)

25. (i) Explain the meaning of the term hybridisation.

.....................................................................................................................................

(1)

(ii) Discuss the bonding in the molecule CH₃CHCH₂ with reference to

· the formation of σ and π bonds

· the length and strength of the Carbon-Carbon bonds

· the types of hybridisation shown by the Carbon atoms

.....................................................................................................................................

(6)

(Total 7 marks)

26. (a) Draw the Lewis structures for the compounds XeF₄, PF₅ and BF₄^–.

(3)

(b) Use the valance shell electron pair repulsion (VSEPR) theory to predict the shapes of the three compounds in (a). State and explain the bond angles in each of the three compounds.

(3)

(Total 6 marks)

27. (a) State the meaning of the term hybridisation. State the type of hybridisation shown by the Nitrogen atoms in N₂, N₂H₂ and N₂H₄.

(4)

(b) By referring to the N₂H₂ molecule describe how sigma (s) and pi (p) bonds form and describe how single and double bonds differ.

(4)

(Total 8 marks)

28. (i) Explain why the first ionisation energy of Magnesium is lower than that of Fluorine.

(2)

(ii) Write an equation to represent the third ionisation energy of magnesium. Explain why the third ionisation energy of Magnesium is higher than that of Fluorine.

(3)

(Total 5 marks)

29. Draw the Lewis structures, state the shapes and predict the bond angles for the following species.

(i) PCl₅

(3)

(ii) SCl₂

(3)

(iii) ICl₄^–

(3)

(Total 9 marks)

30. (a) (i) State the meaning of the term hybridisation.

(1)

(ii) State the type of hybridisation around the Carbon atoms in C60 Fullerene, Diamond and Graphite.

(3)

(iii) Explain why Graphite and C60 Fullerene can conduct electricity.

(2)

(b) (i) Compare how atomic orbitals overlap in the formation of sigma (s) and pi (p) bonds.

(2)

(ii) State the number of sigma bonds and pi bonds in H₂CC(CH₃)CHCH₂.

(2)

(Total 10 marks)

31. (i) Apply the VSEPR theory to deduce the shape of NO₂^-, ICl₅ and SF₄. For each species, draw the Lewis (electron dot) structure, name the shape, and state the value of the bond angle(s).

(9)

(ii) Discuss the bond angle(s) in SF₄.

(1)

(iii) Explain the hybridization involved in the C₂H₄ molecule.

(4)

(iv) State the hybridization involved in the NO₂^- ion and comment on the Nitrogen-Oxygen bond distances.

(2)

(v) Using Table 7 of the Data Booklet, predict and explain which of the bonds O-H, O-N or N-H would be most polar.

(2)

(Total 18 marks)