Chemistry Paper 2 November 2007

1. Aall the outer electrons from one mole of gaseous atoms
2. Bone electron from an atom in the solid state
3. Cone mole of electrons from one mole of gaseous atoms
4. Done mole of electrons from one mole of gaseous $1+$ ions

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1. AGroup I
2. BGroup II
3. CGroup VII
4. DGroup 0

1. A$1s^22s^22p^63s^23p^6$
2. B$1s^22s^22p^6$
3. C$1s^22s^22p^63s^1$
4. D$1s^22s^22p^4$

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1. AD is aluminium; ionisation energy falls steadily because shielding increases faster than nuclear charge.
2. BD is sodium; ionisation energy generally falls because each successive element gains an extra electron shell, increasing shielding.
3. CD is sodium; ionisation energy generally rises because increasing nuclear charge pulls the outer electron in the same shell more strongly as atomic radius decreases.
4. DD is magnesium; the trend levels off because each added electron enters a new principal shell.

1. Aa full outer shell of electrons, which is difficult to remove
2. Ba half-filled outer shell, which is unusually stable
3. Cno electrons in their outer shell at all
4. Da single electron in a new outer shell, which is easily lost

1. Athe pressure above the liquid falls, so dissolved gas becomes less soluble
2. Bthe beer expands as it warms up
3. Cthe beer boils at room temperature
4. Dcarbon dioxide reacts with the air

1. Athe pressure is low and the temperature is high
2. Bthe pressure is high and the temperature is low
3. Cthe pressure is high and the temperature is high
4. Dthe pressure is low and the temperature is low

1. Athe sugar in it crystallises out
2. Bthe alcohol evaporates
3. Cmost of the dissolved carbon dioxide has escaped
4. Dit absorbs oxygen from the air

1. AThe sudden drop in pressure raises the beer's boiling point, causing it to solidify as it cools toward room temperature.
2. BOpening the bottle lets in cold air, which conducts heat away from the beer far faster than the fridge did.
3. CThe sudden drop in pressure lets dissolved carbon dioxide escape rapidly; this endothermic process cools the supercooled beer enough for ice-like solidification.
4. DThe alcohol in the beer reacts with dissolved oxygen, an exothermic reaction that paradoxically lowers the surrounding temperature.

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1. A(i) excess dissolved carbon dioxide formed carbonic acid, giving a sharp taste; (ii) as some $CO_2$ escaped, the carbonation eased toward the expected flavour.
2. B(i) the beer was too cold to taste properly; (ii) it warmed to room temperature.
3. C(i) residual cleaning agent from the glass; (ii) the residue dissolved fully into the beer.
4. D(i) the beer had already started to oxidise; (ii) oxidation slowed as the glass warmed.

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1. Athe glass bottle itself vibrated sharply when opened, physically shaking dissolved gas particles loose from the liquid all at once
2. Bthe sudden pressure drop left the drink supersaturated with dissolved carbon dioxide, and rough nucleation sites let bubbles form and grow rapidly
3. Cthe temperature of the beer rose sharply the instant the cap was removed, boiling off the dissolved gas almost instantly despite the drink being ice-cold
4. Dremoving the cap let atmospheric oxygen rush in and react explosively with the dissolved carbon dioxide, releasing energy that forced the liquid outward

1. Adecreases, because the gas molecules gain enough energy to escape into the surrounding air more easily
2. Bincreases, because warmer liquid molecules move apart, creating more space to dissolve gas
3. Cstays constant, because solubility depends only on pressure, not on temperature
4. Dincreases then decreases, following the same curve as most solids dissolving in water

1. A$+1$
2. B$+3$
3. C$+5$
4. D$+7$

1. A$2Cl^- \rightarrow Cl_2 + 2e^-$
2. B$Cl_2 + 2e^- \rightarrow 2Cl^-$
3. C$Cl_2 + 12OH^- \rightarrow 2ClO_3^- + 6H_2O + 10e^-$
4. D$Cl_2 + 4OH^- \rightarrow 2ClO^- + 2H_2O + 2e^-$

1. A$3.75 \times 10^{-3}$
2. B$3.00 \times 10^{-2}$
3. C$1.50 \times 10^{-3}$
4. D$3.00 \times 10^{-3}$

1. A$0$; $+1$; $+7$
2. B$0$; $-1$; $+5$
3. C$+1$; $0$; $+7$
4. D$0$; $+1$; $+5$

1. A$2Cl^- \rightarrow Cl_2 + 2e^-$
2. B$Cl_2 + 2e^- \rightarrow 2Cl^-$
3. C$Cl_2 + 4OH^- \rightarrow 2ClO^- + 2H_2O + 2e^-$
4. D$Cl_2 + 12OH^- \rightarrow 2ClO_3^- + 6H_2O + 10e^-$

1. A$1.50\times10^{-3}$ mol; $+7$
2. B$3.00\times10^{-3}$ mol; $+4$
3. C$1.06\times10^{-3}$ mol; $+2$
4. D$1.50\times10^{-3}$ mol; $+4$

1. Athe formula of the repeat unit of a polymer
2. Bthe actual number of atoms of each element in one molecule
3. Cthe simplest whole number ratio of the atoms present
4. Dthe formula which shows all the bonds present

1. A$C_8H_6O_4$
2. B$C_3H_2O_2$
3. C$C_2H_2O$
4. D$C_4H_3O_2$

1. Abenzene-1,4-dicarboxylic acid
2. B2-hydroxybenzoic acid
3. Cbenzoic acid
4. Dethanedioic acid

1. A$C_8H_6O_4$; ethane-1,2-diol; polyester
2. B$C_4H_3O_2$; ethane-1,2-diol; polyamide
3. C$C_8H_6O_4$; 1,6-diaminohexane; polyester
4. D$C_8H_6O_4$; ethanol; polyester

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1. Acarries a positive charge
2. Baccepts a pair of electrons
3. Chas an unpaired electron
4. Dhas a lone pair of electrons

1. A$Cl \cdot + CH_3CH_2CH_3 \rightarrow CH_3CH_2CH_2 \cdot + HCl$
2. B$CH_3CH_2CH_2 \cdot + Cl_2 \rightarrow CH_3CH_2CH_2Cl + Cl \cdot$
3. C$2Cl \cdot \rightarrow Cl_2$
4. D$Cl_2 \xrightarrow{uv} 2Cl \cdot$

1. Aammonia in ethanol
2. Bacidified potassium dichromate(VI)
3. Caqueous sodium hydroxide
4. Dethanolic potassium hydroxide

1. Apropagation: $2Cl\cdot \rightarrow Cl_2$; termination: $Cl\cdot + CH_3CH_2CH_3 \rightarrow CH_3CH_2CH_2\cdot + HCl$
2. Bpropagation: $Cl\cdot + CH_3CH_2CH_3 \rightarrow CH_3CH_2CH_2\cdot + HCl$; termination: $CH_3CH_2CH_2\cdot + Cl\cdot \rightarrow CH_3CH_2CH_2Cl$
3. Cpropagation: $CH_3CH_2CH_2\cdot + Cl\cdot \rightarrow CH_3CH_2CH_2Cl$; termination: $Cl_2 \xrightarrow{uv} 2Cl\cdot$
4. Dpropagation: $Cl_2 \xrightarrow{uv} 2Cl\cdot$; termination: $2Cl\cdot \rightarrow Cl_2$

1. Aconcentrated sulfuric acid, cold; W = $(CH_3)_2CHOSO_3H$; electrophilic addition
2. Bpotassium cyanide in ethanol, reflux; W = $(CH_3)_2CHCN$; nucleophilic substitution
3. Cammonia in ethanol, heat and pressure; W = $(CH_3)_2CHNH_2$; nucleophilic substitution
4. Daqueous sodium hydroxide, warm; W = $(CH_3)_2CHOH$; nucleophilic substitution

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1. Aacidified potassium dichromate(VI) under heat, the reagent normally used to oxidise alcohols
2. Blithium aluminium hydride in dry ether, followed by dilute acid work-up
3. Chydrogen gas with no catalyst present, simply left at room temperature
4. Daqueous sodium hydroxide under warm reflux conditions, the same reagent used for step II

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