Chemistry Paper 2 November 2023

1. A$C_2H_4O$
2. B$CH_2O$
3. C$CH_3O$
4. D$C_2H_6O$

1. A$C_2H_6O_2$
2. B$C_3H_9O_3$
3. C$CH_3O$
4. D$C_2H_6O$

1. Asparingly soluble in water, because only one $-OH$ group is exposed
2. Bvery soluble in water, because it forms hydrogen bonds with water
3. Cinsoluble in water, because it is a large molecule
4. Dinsoluble in water, because it is non-polar

1. Adepletion of the stratospheric ozone layer, since unburnt ethane-1,2-diol vapour is thought to react directly with ozone molecules.
2. Beutrophication of nearby rivers and lakes, since any unburnt fuel is assumed to wash directly into the local water supply.
3. Cwidespread radioactive contamination of the soil surrounding the site where the fuel was originally burned.
4. Dglobal warming from the carbon dioxide released, and acid rain from oxides of nitrogen and sulfur formed during combustion.

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1. A$NH_3 + H_2O \rightleftharpoons NH_4^+ + OH^-$
2. B$NH_3 + H^+ \rightarrow NH_4^+$
3. C$NH_4^+ + OH^- \rightarrow NH_3 + H_2O$
4. D$NH_4Cl \rightarrow NH_3 + HCl$

1. A0.004 and $0.003\ mol\,dm^{-3}$
2. B0.002 and $0.0015\ mol\,dm^{-3}$
3. C0.008 and $0.006\ mol\,dm^{-3}$
4. D0.001 and $0.00075\ mol\,dm^{-3}$

1. A4.86
2. B8.86
3. C9.14
4. D9.42

1. A$NH_4Cl \rightarrow NH_3 + HCl$
2. B$NH_3 + H_2O \rightleftharpoons NH_4^+ + OH^-$
3. C$NH_4^+ + OH^- \rightarrow NH_3 + H_2O$
4. D$NH_3 + H^+ \rightarrow NH_4^+$

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1. Ais an ionic compound whose ions are readily hydrated (surrounded) by polar water molecules.
2. Bis a purely covalent molecule that mixes with water only by weak van der Waals forces, much like an oil.
3. Creacts completely with water, decomposing entirely into ammonia gas and hydrochloric acid.
4. Dis non-polar, allowing it to dissolve freely in water by simple diffusion.

1. A$ns^2np^2$
2. B$ns^2np^4$
3. C$ns^1np^3$
4. D$ns^2np^1$

1. A$2NO + O_2 \rightarrow 2NO_2$
2. B$N_2 + 2O_2 \rightarrow 2NO_2$
3. C$N_2 + O_2 \rightarrow 2NO$
4. D$N_2 + 3H_2 \rightleftharpoons 2NH_3$

1. Abecomes more electronegative
2. Bforms a more covalent nitrate
3. Ccarries a greater charge
4. Dbecomes larger and polarises the nitrate ion less

1. Adelocalisation across each graphite layer gives its C-C bonds some multiple-bond character, so they are shorter and stronger than diamond's bonds.
2. Bgraphite is actually held together by strong ionic bonds between its stacked layers, stronger overall than diamond's purely covalent bonds.
3. Cdiamond's own covalent bonds are inherently weaker than graphite's, since diamond is held together only by weak van der Waals forces throughout its structure.
4. Dgraphite conducts electricity while diamond does not, and any structure capable of conducting electricity always has a higher melting point as a result.

1. Anitrogen molecules are simply far too large in physical size to collide effectively with other reacting molecules.
2. Bthe N≡N triple bond is very strong (about 944 kJ/mol), requiring a large amount of energy to break.
3. Cnitrogen atoms have no lone pairs of electrons available for forming any kind of new chemical bond at all.
4. Dnitrogen atoms are considered to have a full outer electron shell, behaving chemically much like the noble gases do.

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1. AHCN is too volatile at low pH
2. Bthe alkali neutralises the product
3. Cthe attacking nucleophile is $CN^-$, which HCN alone provides too slowly
4. Dthe aldehyde is oxidised in acid

1. Aphenol
2. Bmethylbenzene
3. Cbenzoic acid
4. Dphenylmethanol

1. Ais a very good conductor of heat
2. Breacts readily with dilute acids
3. Chas a low melting point
4. Dgives an attractive finish and protects the steel from rusting

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