DP Chemistry Questionbank

(i) Suggest why incomplete combustion of plastic, such as polyvinyl chloride, is common in industrial and house fires.

(ii) Phthalate plasticizers such as DEHP, shown below, are frequently used in polyvinyl chloride.

With reference to bonding, suggest a reason why many adults have measurable levels of phthalates in their bodies.

A chloride of titanium, TiCl₄, melts at 248 K. Suggest why the melting point is so much lower than that of KCl.

Determine the type of bond present in SbBr₃, showing your method. Use sections 8 and 29 of the data booklet.

Which bonds cause the boiling point of water to be significantly greater than that of hydrogen sulfide?

A.     London (dispersion)

B.     Covalent

C.     Ionic

D.     Hydrogen

State and explain the difference in bond strength between the nitrogen atoms in a hydrazine and nitrogen molecule.

Which of these species contains the shortest carbon to oxygen bond length?

A.  ${\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{O}}^{-}$

B.  ${\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{OH}$

C.  ${\mathrm{CH}}_3{\mathrm{COO}}^{-}$

D.  ${\mathrm{CH}}_3\mathrm{COOH}$

Which compound has the shortest C–N bond?

A. CH₃NH₂

B. (CH₃)₃CNH₂

C. CH₃CN

D. CH₃CHNH

Which compound contains both ionic and covalent bonds?

A.  $\text{MgO}$

B.  ${\text{CH}}_{\text{2}}{\text{Cl}}_{\text{2}}$

C.  ${\text{CH}}_{\text{3}}\text{COOH}$

D.  $\text{NaOH}$

Which compound has the shortest C to N bond?

A.  HCN

B.  CH₃CH₂NH₂

C.  CH₃CHNH

D.  (CH₃)₂NH

What are the predicted electron domain geometries around the carbon and both nitrogen atoms in urea, (NH₂)₂CO, applying VSEPR theory?

Explain why the hydrides of group 16 elements (H₂O, H₂S, H₂Se and H₂Te) are polar molecules.

The graph shows the boiling points of the hydrides of group 16 elements.

Explain the increase in the boiling point from H₂S to H₂Te.

Outline two differences between the bonding of carbon atoms in C₆₀ and diamond.

Explain why C₆₀ and diamond sublime at different temperatures and pressures.

Compare, giving a reason, the length of the bond between the carbon atoms in ethyne with that in ethane, C₂H₆.

Identify the type of bonding in sodium hydrogencarbonate.

Between sodium and hydrogencarbonate:

Between hydrogen and oxygen in hydrogencarbonate:

Compare, giving a reason, the length of the bond between the carbon atoms in ethyne with that in ethane, C₂H₆.

Identify the type of bonding in sodium hydrogencarbonate.

Between sodium and hydrogencarbonate:

Between hydrogen and oxygen in hydrogencarbonate:

Determine the percentage of ionic bonding in alumina using sections 8 and 29 of the data booklet.