DP Chemistry Questionbank

(i) Uranium hexafluoride, UF₆, is used in the uranium enrichment process that produces fuel for nuclear reactors.

State the molecular shape of uranium hexafluoride.

(ii) Explain why uranium dioxide, UO₂, has a very high melting point whereas uranium hexafluoride vapourises easily into gas.

State the type of bonding in potassium chloride which melts at 1043 K.

Lanthanum has a similar electronegativity to group 2 metals. Explain, in terms of bonding and structure, why crystalline lanthanum bromide is brittle.

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

Which of the following does not react with dilute HCl(aq)?

A.     Na₂CO₃

B.     Cu

C.     Zn

D.     CuO

Explain the electrical conductivity of molten Na₂O and P₄O₁₀.

Describe the nature of ionic bonding.

What is the formula of ammonium phosphate?

A.     (NH₃)₃PO₄

B.     (NH₄)₃PO₄

C.     (NH₄)₂PO₄

D.     (NH₃)₂PO₃

Describe the nature of ionic bonding.

Describe the structure and bonding in solid sodium oxide.

Identify the type of bonding in sodium hydrogencarbonate.

Between sodium and hydrogencarbonate:

Between hydrogen and oxygen in hydrogencarbonate:

What is the IUPAC name of NiCO₃?

A. nickel(II) carbonate

B. nickel carbonate

C. nickel(I) carbonate

D. nitrogen(I) carbonate

Describe the structure and bonding in solid sodium oxide.

Identify the type of bonding in sodium hydrogencarbonate.

Between sodium and hydrogencarbonate:

Between hydrogen and oxygen in hydrogencarbonate:

Aspirin, C₆H₄(OCOCH₃)COOH, is only slightly soluble in water.

Outline, including an equation, how aspirin can be made more water-soluble. Use section 37 in the data booklet.

Which formula is correct?

A.  ${\mathrm{NH}}_4{\mathrm{PO}}_4$

B.  ${\left({\mathrm{NH}}_4\right)}_2{\mathrm{PO}}_4$

C.  ${\left({\mathrm{NH}}_4\right)}_3{\mathrm{PO}}_4$

D.  ${\left({\mathrm{NH}}_4\right)}_3{\left({\mathrm{PO}}_4\right)}_2$

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.  $\text{NaOH}$

What is the formula of the compound formed from Ca²⁺ and PO₄³⁻?

A.  CaPO₄

B.  Ca₃(PO₄)₂

C.  Ca₂(PO₄)₃

D.  Ca(PO₄)₂

Which statement best describes the intramolecular bonding in HCN (l)?

A. Electrostatic attractions between H⁺ and CN⁻ ions

B. Hydrogen bonding

C. Van der Waals forces and hydrogen bonding

D. Electrostatic attractions between pairs of electrons and positively charged nuclei

What is the name of the compound with formula Ti₃(PO₄)₂?

A. Titanium phosphate

B. Titanium(II) phosphate

C. Titanium(III) phosphate

D. Titanium(IV) phosphate

State the types of bonding in magnesium, oxygen and magnesium oxide, and how the valence electrons produce these types of bonding.

State the types of bonding in magnesium, oxygen and magnesium oxide, and how the valence electrons produce these types of bonding.

(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 compound has the shortest C–N bond?

A. CH₃NH₂

B. (CH₃)₃CNH₂

C. CH₃CN

D. CH₃CHNH

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.

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.

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 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

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

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

The Lewis (electron dot) structure of the ethanedioate ion is shown below.

Outline why all the C–O bond lengths in the ethanedioate ion are the same length and suggest a value for them. Use section 10 of the data booklet.

Draw the Lewis (electron dot) structure of the ethanedioate ion, ^–OOCCOO^–.

Outline why all the C–O bond lengths in the ethanedioate ion are the same length and suggest a value for them. Use section 10 of the data booklet.

(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.

Which combination describes the sulfate(IV) ion, SO₃^2– (also known as sulfite ion)?

Estimate the H−N−H bond angle in methanamine using VSEPR theory.

State the electron domain geometry around the nitrogen atom and its hybridization in methanamine.

Deduce the Lewis (electron dot) structure and molecular geometry of PCl₃.

Deduce the Lewis (electron dot) structures of ozone.

Deduce one resonance structure of ozone and the corresponding formal charges on each oxygen atom.

Estimate the H−N−H bond angle in methanamine using VSEPR theory.

Ammonia reacts reversibly with water.
$$\text{N}{\text{H}}_{\text{3}}\text{(g)}+{\text{H}}_{\text{2}}\text{O(l)}\rightleftharpoons {\text{NH}}_{\text{4}}^{+}\text{(aq)}+\text{O}{\text{H}}^{-}\text{(aq)}$$
Explain the effect of adding ${\text{H}}^{+}\text{(aq)}$ ions on the position of the equilibrium.

Draw the Lewis (electron dot) structures of PF₃ and PF₄⁺ and use the VSEPR theory to deduce the molecular geometry of each species.

Predict with a reason, whether the molecule PF₃ is polar or non-polar.

Draw the Lewis (electron dot) structures of PF₃ and PF₅ and use the VSEPR theory to deduce the molecular geometry of each species including bond angles.

Predict whether the molecules PF₃ and PF₅ are polar or non-polar.

The structural formula of urea is shown.

Predict the electron domain and molecular geometries at the nitrogen and carbon atoms, applying the VSEPR theory.

Carbon and silicon are elements in group 14.

Explain why CO₂ is a gas but SiO₂ is a solid at room temperature.

The structural formula of urea is shown.

Predict the electron domain and molecular geometries at the nitrogen and carbon atoms, applying the VSEPR theory.

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

Lewis structures show electron domains and are used to predict molecular geometry.

Deduce the electron domain geometry and the molecular geometry for the NH₂⁻ ion.

Graphene is two-dimensional, rather than three-dimensional, material.

Justify this by using the structure of graphene and information from the table.

Show that graphene is over 1600 times stronger than graphite.

Identify a value from the table which can be used to support the information about graphene given below.

Electrons in a solid are restricted to certain ranges, or bands, of energy (vertical axis). In an insulator or semiconductor, an electron bound to an atom can break free only if it gets enough energy from heat or a passing photon to jump the “band gap”, but in graphene the gap is infinitely small.

Diamond, graphene, and graphite are all network solids.

Suggest, giving a reason, the electron mobility of diamond compared to graphene.

The melting point of diamond at 1 × 10⁶ kPa is 4200 K (in the absence of oxygen).

Suggest, based on molecular structure, why graphene has a higher melting point under these conditions.

Draw the Lewis (electron dot) structure for BrO₃⁻ that obeys the octet rule.

Draw two Lewis (electron dot) structures for BrO₃⁻.

Draw a Lewis (electron dot) structure of chloramine.

Deduce the molecular geometry of chloramine and estimate its H–N–H bond angle.

Molecular geometry:

H–N–H bond angle:

State the type of bond formed when chloramine is protonated.

Deduce the Lewis (electron dot) structure of ethyne.

State, giving a reason, the shape of the dinitrogen monoxide molecule.

Draw a Lewis (electron dot) structure of chloramine.

Deduce the molecular geometry of chloramine and estimate its H–N–H bond angle.

Molecular geometry:

H–N–H bond angle:

Deduce the Lewis (electron dot) structure of ethyne.

What is the structure and bonding in SiO₂(s)?

Which molecule is most polar?

A.  ${\mathrm{CHF}}_3$

B.  ${\mathrm{CF}}_4$

C.  ${\mathrm{CClF}}_3$

D.  ${\mathrm{CCl}}_4$

Which combination correctly describes the geometry of the carbonate ion, ${{\mathrm{CO}}_3}^{2-}$?

Draw the Lewis (electron dot) structure of hydrogen sulfide.

Draw a Lewis (electron dot) structure for ozone.

Deduce the Lewis (electron dot) structure and molecular geometry of sulfur dichloride, SCl₂.

Deduce the Lewis (electron dot) structure and molecular geometry of sulfur tetrafluoride, SF₄, and sulfur dichloride, SCl₂.

Sketch the Lewis (electron dot) structure of the P₄ molecule, containing only single bonds.

Sketch the Lewis (electron dot) structure of the P₄ molecule, containing only single bonds.

Draw the Lewis (electron dot) structure of the ammonia molecule.

Deduce a Lewis (electron dot) structure of the nitric acid molecule, HNO₃, that obeys the octet rule, showing any non-zero formal charges on the atoms.

Explain the electron domain geometry of SO₃.

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

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

Explain why the boiling point of ethane-1,2-diol is significantly greater than that of ethene.

The table below shows average figures for the percentage fatty acid composition of some common fats and oils.

(i) Deduce, with a reason, which fat or oil from the table above has the lowest iodine number.

(ii) Deduce, with a reason, which fat or oil from the table above is most likely to become rancid when exposed to the air.

(iii) The P/S index of a fat or oil is the ratio of polyunsaturated fat to saturated fat present. It is sometimes used to compare the relative health benefits of different lipids in the diet. Calculate the P/S index of beef fat and soybean oil.

(iv) Suggest why a P/S index of greater than 1 is considered beneficial to health.

(v) Cotton seed oil and corn oil have similar iodine numbers but the melting point of cotton seed oil is higher than that of corn oil. Suggest an explanation in terms of the structure and bonding in these two oils.

(i) Uranium hexafluoride, UF₆, is used in the uranium enrichment process that produces fuel for nuclear reactors.

State the molecular shape of uranium hexafluoride.

(ii) Explain why uranium dioxide, UO₂, has a very high melting point whereas uranium hexafluoride vapourises easily into gas.

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

Explain why the difference in their structures affects their melting points.

The drain pipe of a kitchen sink can become clogged by fatty acids, such as linoleic acid, C₁₈H₃₂O₂, but not by the trisaccharide, raffinose, C₁₈H₃₂O₁₆, containing the same number of carbon atoms.

Explain why raffinose is far more water soluble than linoleic acid.

The solubility of a vitamin depends on its structure.

Identify the vitamin given in section 35 of the data booklet that is the most soluble in water.

Suggest why aspirin is slightly soluble in water. Refer to section 37 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 why hydrazine has a higher boiling point than dinitrogen tetraoxide.

Explain which one of these fatty acids has the highest boiling point.

Suggest, in terms of its structure, why vitamin D is fat-soluble using section 35 of the data booklet.

Explain why diamorphine passes more readily than morphine through the blood-brain barrier.

Explain why the melting points of the group 1 metals (Li → Cs) decrease down the group.

Explain why the melting points of the group 1 metals (Li → Cs) decrease down the group whereas the melting points of the group 17 elements (F → I) increase down the group.

Describe how the structures of LDPE and HDPE affect one mechanical property of the plastics.

Explain how the inclusion of carbohydrates in plastics makes them biodegradable.

Explain, at the molecular level, why vitamin D is soluble in fats. Use section 35 of the data booklet.

Identify the type of intermolecular bonding that is responsible for Kevlar^®’s strength.

Suggest one reason why urea is a solid and ammonia a gas at room temperature.

Sketch two different hydrogen bonding interactions between ammonia and water.

Carbon and silicon are elements in group 14.

Explain why CO₂ is a gas but SiO₂ is a solid at room temperature.

What are the strongest intermolecular forces between molecules of propanone, CH₃COCH₃, in the liquid phase?

A.     London (dispersion) forces

B.     Covalent bonding

C.     Hydrogen bonding

D.     Dipole–dipole forces

Suggest one reason why urea is a solid and ammonia a gas at room temperature.

Sketch two different hydrogen bonding interactions between ammonia and water.

Part of this molecule is hydrophilic (bonds readily to water) and part hydrophobic (does not bond readily to water). Draw a circle around all of the hydrophilic part of the molecule.

When a small amount of palmitic acid is placed in water it disperses to form a layer on the surface that is only one molecule thick. Explain, in terms of intermolecular forces, why this occurs.

The compounds shown below have similar relative molecular masses. What is the correct order of increasing boiling point?

A.     CH₃COOH < (CH₃)₂CO < (CH₃)₂CHOH

B.     CH₃COOH < (CH₃)₂CHOH < (CH₃)₂CO

C.     (CH₃)₂CO < CH₃COOH < (CH₃)₂CHOH

D.     (CH₃)₂CO < (CH₃)₂CHOH < CH₃COOH

Suggest why aspirin is slightly soluble in water. Refer to section 37 of the data booklet.

Suggest how benzoic acid, M_r = 122.13, forms an apparent dimer, M_r = 244.26, when dissolved in a non-polar solvent such as hexane.

Identify the type of interaction that must be overcome when liquid ethyne vaporizes.

Explain why product B is water soluble.

What is the order of increasing boiling point?

A. CH₃CH₂CH₂CH₃ < CH₃CH(OH)CH₃ < CH₃COCH₃ < CH₃CO₂H

B. CH₃CH₂CH₂CH₃ < CH₃COCH₃ < CH₃CH(OH)CH₃ < CH₃CO₂H

C. CH₃CO₂H < CH₃COCH₃ < CH₃CH(OH)CH₃ < CH₃CH₂CH₂CH₃

D. CH₃CH₂CH₂CH₃ < CH₃COCH₃ < CH₃CO₂H < CH₃CH(OH)CH₃

Suggest how benzoic acid, M_r = 122.13, forms an apparent dimer, M_r = 244.26, when dissolved in a non-polar solvent such as hexane.

Identify the type of interaction that must be overcome when liquid ethyne vaporizes.

Explain why product B is water soluble.

What is the order of increasing boiling point?

A. CH₃CH₂CH₂CH₃ < CH₃CH(OH)CH₃ < CH₃COCH₃ < CH₃CO₂H

B. CH₃CH₂CH₂CH₃ < CH₃COCH₃ < CH₃CH(OH)CH₃ < CH₃CO₂H

C. CH₃CO₂H < CH₃COCH₃ < CH₃CH(OH)CH₃ < CH₃CH₂CH₂CH₃

D. CH₃CH₂CH₂CH₃ < CH₃COCH₃ < CH₃CO₂H < CH₃CH(OH)CH₃

Explain why the compound C₃H₈O, produced in (a)(iv), has a higher boiling point than compound C₃H₆O, produced in d(i).

Explain why the compound C₂H₆O, produced in (b), has a higher boiling point than compound C₂H₄O, produced in d(i).

Suggest why a non-polar solvent was needed.

Proteins are polymers of amino acids.

The mixture is composed of glycine, $\mathrm{Gly}$, and isoleucine, $\mathrm{Ile}$. Their structures can be found in section 33 of the data booklet.

Deduce, referring to relative affinities and ${\mathrm{R}}_{\mathrm{f}}$, the identity of A1.

State the most significant intermolecular forces in the phospholipid in b(i).

Proteins are polymers of amino acids.

The mixture is composed of glycine, $\mathrm{Gly}$, and isoleucine, $\mathrm{Ile}$. Their structures can be found in section 33 of the data booklet.

Deduce, referring to relative affinities and ${\mathrm{R}}_{\mathrm{f}}$, the identity of A1.

Suggest a reason that the Winkler Method used to measure biochemical oxygen demand (BOD) must be done at constant temperature.

Which statement best describes the intramolecular bonding in HCN (l)?

A. Electrostatic attractions between H⁺ and CN⁻ ions

B. Hydrogen bonding

C. Van der Waals forces and hydrogen bonding

D. Electrostatic attractions between pairs of electrons and positively charged nuclei

What is the main interaction between liquid CH₄ molecules?

A.  London (dispersion) forces

B.  Dipole–dipole forces

C.  Hydrogen bonding

D.  Covalent bonding

Suggest why hydrogen chloride, HCl, has a lower boiling point than hydrogen cyanide, HCN.

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

Describe the bonding in metals.

Explain why an aluminium-titanium alloy is harder than pure aluminium.

Suggest why the melting point of vanadium is higher than that of titanium.

Explain why the melting points of the group 1 metals (Li → Cs) decrease down the group.

Explain why the melting points of the group 1 metals (Li → Cs) decrease down the group whereas the melting points of the group 17 elements (F → I) increase down the group.

Outline why solid calcium is a good conductor of electricity.

Outline why solid calcium is a good conductor of electricity.

Which series shows the correct order of metallic bond strength from strongest to weakest?

A.  $\mathrm{Na}>\mathrm{K}>\mathrm{Rb}>\mathrm{Mg}$

B.  $\mathrm{Mg}>\mathrm{Rb}>\mathrm{K}>\mathrm{Na}$

C.  $\mathrm{Rb}>\mathrm{K}>\mathrm{Na}>\mathrm{Mg}$

D.  $\mathrm{Mg}>\mathrm{Na}>\mathrm{K}>\mathrm{Rb}$

Alloying metals changes their properties. Suggest one property of magnesium that could be improved by making a magnesium–CNT alloy.

Describe the bonding in iron, Fe (s).