Chemistry Paper 2 November 2015

1. A0.40 g
2. B0.78 g
3. C1.82 g
4. D6.66 g

1. A$C_3H_6O$
2. B$C_3H_8O$
3. C$C_4H_{10}O$
4. D$C_2H_6O$

1. Athe molecular ion
2. B$CH_3^+$
3. C$C_2H_5^+$
4. D$C_2H_5O^+$

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1. A$C_2H_5O^+$
2. Bthe molecular ion, $C_3H_8O^+$
3. C$CH_3^+$
4. D$C_2H_5^+$

1. Athe molecular ion, $C_3H_8O^+$, with no fragmentation at all
2. B$CH_3^+$, formed by loss of the rest of the chain
3. C$C_2H_5O^+$, formed by loss of a methyl radical from the molecular ion
4. D$C_2H_5^+$, formed by loss of the oxygen-containing fragment

1. A$\frac{p_{NO_2}^2}{p_{N_2O_4}}$, atm
2. B$\frac{p_{N_2O_4}}{p_{NO_2}^2}$, $atm^{-1}$
3. C$\frac{p_{NO_2}}{p_{N_2O_4}}$, no units
4. D$\frac{2p_{NO_2}}{p_{N_2O_4}}$, atm

1. A7.20 mol
2. B8.00 mol
3. C0.40 mol
4. D3.60 mol

1. Aleave $K_c$ unchanged
2. Bmake $K_c$ negative
3. Clower the value of $K_c$
4. Draise the value of $K_c$

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1. Adissociation of $N_2O_4$ is endothermic, so cooling favours the exothermic reverse reaction and reduces $[NO_2]$ relative to $[N_2O_4]$
2. Bthe gas constant $R$ becomes smaller as the temperature of the system falls
3. Cthe equilibrium position is independent of temperature and only pressure changes shift it
4. Dcooling speeds up the forward reaction much more than the reverse reaction

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1. Atetrahedral, with four bonding regions around nitrogen
2. Btrigonal planar, with three regions of electron density around nitrogen
3. Clinear, with two regions of electron density around nitrogen
4. Dbent (V-shaped), like the shape of water

1. A$[Ar]3d^{10}4s^1$
2. B$[Ar]3d^9$
3. C$[Ar]3d^{10}$
4. D$[Ar]3d^94s^1$

1. Aan ion with a partially filled d subshell
2. Btwo or more metal atoms bonded together
3. Ca metal ion surrounded by water only
4. Da central metal ion datively bonded to ligands

1. Aprovides fewer delocalised electrons per atom
2. Bhas a larger nuclear charge
3. Chas a giant covalent structure
4. Dforms only the $+2$ oxidation state

1. Aforms one or more stable ions with a partially filled d subshell
2. Bhas a completely filled d subshell in all of its common ions
3. Cis found only among the first three periods of the periodic table
4. Dforms only one stable oxidation state, always $+2$

1. Athe solution turns colourless, then slowly green as more ammonia is added
2. Ba pale blue precipitate forms first, which then dissolves in excess ammonia to give a deep blue solution
3. Ca white precipitate forms and stays insoluble even in excess ammonia
4. Dno visible change occurs at any stage of the addition

1. Athe precipitate is oxidised by excess ammonia to a soluble copper(III) salt
2. Bexcess ammonia neutralises the precipitate as if it were a simple acid
3. Cammonia ligands substitute for water/hydroxide ligands around $Cu^{2+}$, forming a soluble complex ion
4. Dthe precipitate simply dilutes below its solubility limit as more liquid is added

1. Adecreases steadily across the series
2. Bstays approximately constant across the series
3. Cincreases then drops sharply at copper
4. Dincreases steadily across the series

1. Aatomic mass rises while atomic radius falls, packing more mass into a smaller volume
2. Bthe number of protons falls while the number of neutrons stays fixed
3. Cthe elements gradually change from metallic to covalent bonding
4. Deach element gains an extra electron shell not present in the last

1. Afunctional group
2. Bpositional
3. Coptical
4. Dcis-trans

1. A2-methylpropan-2-ol
2. Bmethoxypropane
3. Cbutan-2-ol
4. D2-methylpropan-1-ol

1. AW, because it is a secondary alcohol
2. BZ, because it is a primary alcohol
3. CZ, because it is oxidised to a ketone
4. DW, because it is a primary alcohol

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1. Atwo secondary alcohols
2. Ba primary alcohol and a secondary alcohol
3. Ca secondary alcohol and a primary alcohol
4. Da primary alcohol and a tertiary alcohol

1. Aboth alcohols resist oxidation entirely, so the dichromate colour never changes
2. Bonly W turns the dichromate from orange to green; Z gives no colour change at all
3. Conly Z turns the dichromate from orange to green; W gives no colour change at all
4. Dboth alcohols turn the orange dichromate green, but only W's oxidation product (an aldehyde) further reduces Tollens' reagent to a silver mirror

1. Aa silver mirror, but only after several hours of standing
2. Bthe same silver mirror as the aldehyde from W, since both are carbonyl compounds
3. Cno silver mirror, because a ketone has no hydrogen atom on its carbonyl carbon and cannot be oxidised further by Tollens' reagent
4. Da black precipitate of silver oxide instead of a mirror

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1. Aionic polymerisation
2. Baddition polymerisation
3. Cfree radical polymerisation
4. Dcondensation polymerisation

1. Aethanoic acid and an alcohol
2. Bethanol and a carboxylic acid
3. Cethanamide and an alcohol
4. Dcarbon dioxide and an amine

1. Ano visible change
2. Ba white precipitate of silver chloride
3. Ca cream precipitate soluble in dilute ammonia
4. Da yellow precipitate insoluble in ammonia

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1. Acarbon dioxide and an amine derivative of choline
2. Bethanoic acid and choline, $HOCH_2CH_2N^+(CH_3)_3$
3. Cethanol and a carboxylic acid derivative of choline
4. Dethanamide, $CH_3CONH_2$, and choline, $HOCH_2CH_2N^+(CH_3)_3$

1. Areacts with water to precipitate a white solid of the free amine
2. Bdoes not dissolve at all, since quaternary ammonium salts are covalent and insoluble
3. Cdissolves completely, dissociating fully into $(CH_3)_4N^+$ and $Cl^-$ ions, since it is a fully ionic salt
4. Dhydrolyses in the water to give methanol and trimethylamine gas