Chemistry Paper 3 November 2022

1. Aoverlap of an s orbital with a hybrid orbital
2. Bend-on overlap of two s orbitals
3. Cend-on overlap of two hybrid orbitals
4. Dsideways overlap of two unhybridised p orbitals

1. Aoxygen
2. Bcarbon dioxide
3. Chydrogen
4. Dnitrogen

1. A0.80 atm
2. B0.24 atm
3. C0.30 atm
4. D0.45 atm

1. Asideways overlap of unhybridised p orbitals
2. Bend-on overlap of two hybrid orbitals
3. Coverlap of two unhybridised d orbitals
4. Doverlap of an s orbital with a d orbital

1. Aforms only between two atoms of the same element
2. Brestricts rotation about the bond axis
3. Crequires no overlap between atomic orbitals
4. Dis stronger than the sigma bond linking the same atoms

1. Ahigh pressure and low temperature
2. Bhigh pressure and high temperature
3. Clow pressure and low temperature
4. Dlow pressure and high temperature

1. Alarge and non-polar with a high molar mass
2. Bsmall and non-polar, with weak intermolecular forces
3. Clarge and polar, with strong intermolecular forces
4. Dsmall but strongly polar, favouring hydrogen bonding

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1. Ahave a lower molar mass than hydrogen molecules, which is unrelated to intermolecular forces
2. Bhave more electrons and stronger van der Waals forces
3. Care polar molecules, unlike the non-polar hydrogen molecule
4. Doccupy no volume at all inside the container, unlike real molecules

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1. Athe lone pair on nitrogen repels the bonding pairs more strongly than a bonding pair does
2. Bthe N–H bond is shorter than the C–H bond
3. Cnitrogen is more electronegative than carbon
4. Dthere are only three bonding pairs of electrons

1. A−1 072 kJmol⁻¹
2. B−536 kJmol⁻¹
3. C+536 kJmol⁻¹
4. D+1 072 kJmol⁻¹

1. A4.59
2. B8.74
3. C9.41
4. D10.26

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1. Aincreasing the rate of a reaction
2. Bprecipitating heavy metal ions from solution
3. Cmaintaining a constant pH in blood
4. Dreducing the solubility of a salt

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1. Abond energy of bonds formed minus bond energy of bonds broken
2. Bactivation energy minus total bond energy
3. Cthe sum of all the bond energies in the equation
4. Dbond energy of bonds broken minus bond energy of bonds formed

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1. Azero
2. Bfirst
3. Csecond
4. Dthird

1. Athe temperature of the mixture has fallen
2. Bthe concentration of hydrogen peroxide is lower, so collisions are less frequent
3. Cthe activation energy of the reaction has increased
4. Dall the hydrogen peroxide has been used up

1. A$1.4 \times 10^{-10}$ mol³dm⁻⁹
2. B$5.6 \times 10^{-10}$ mol³dm⁻⁹
3. C$2.5 \times 10^{-9}$ mol³dm⁻⁹
4. D$7.5 \times 10^{-7}$ mol³dm⁻⁹

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1. Ameasuring the electrical conductivity of the solid manganese dioxide catalyst used
2. Bweighing the closed, sealed reaction vessel only once, right at the very end of the run
3. Cperiodically titrating the remaining H2O2 with KMnO4 of known concentration
4. Dmeasuring the freezing point of the reaction mixture repeatedly at set time intervals

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1. Ais less than Ksp
2. Bcannot be compared with Ksp
3. Cequals Ksp exactly
4. Dexceeds Ksp

1. Ameasuring the volume of oxygen gas evolved over time
2. Bmeasuring the refractive index of the pure water solvent
3. Cmeasuring the melting point of the solution at intervals
4. Dmeasuring the mass of the sealed, unopened reaction flask

1. Athe tetrachlorides become more polar down the group
2. Bthe bond energies decrease down the group
3. Cthe molecules become larger, so the van der Waals forces between them are stronger
4. Dthe bonds become more ionic down the group

1. Ano precipitate is formed
2. Ba white precipitate is formed
3. Ca cream precipitate is formed
4. Da yellow precipitate is formed

1. Asilver iodide is denser than silver chloride
2. Bammonia reacts with the iodide ions
3. Cammonia cannot reach the surface of the silver iodide
4. Dthe $K_{sp}$ of silver iodide is so small that its ionic product stays above $K_{sp}$ even when $[Ag^+]$ is lowered

1. Aa cream precipitate forms
2. Ba yellow precipitate forms
3. Cno visible change occurs
4. Da white precipitate forms

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1. Athe covalent bonds become longer and weaker as atomic radius increases
2. Bthe tetrachloride molecules become noticeably more polar down the group as size increases
3. Cthe boiling points of the tetrachlorides simply decrease steadily down the whole group
4. Dthe central atoms become progressively more electronegative down the whole group

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1. Asolubility cannot be compared using Ksp
2. BAgCl
3. CAgI
4. Dboth are equally soluble

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1. Ablack lung disease
2. Bminamata disease
3. Cblue-baby syndrome
4. Ditai-itai disease

1. Aalgal overgrowth blocks light and its later decay by bacteria depletes dissolved oxygen
2. Bnitrate ions dissolved in the water directly poison the gills of the fish on contact with them there
3. Cnitrate ions raise the overall temperature of the water body quite significantly
4. Dnitrate ions react directly with the water molecules to release toxic chlorine gas

1. Aoxidises Fe2+ to Fe3+ in haemoglobin, reducing oxygen transport
2. Bbinds directly to oxygen molecules while still inside the lungs
3. Cdestroys red blood cells directly by osmotic lysis in the blood
4. Dreacts with stomach acid to release toxic chlorine gas

1. Asilicon
2. Bsulphur
3. Csodium
4. Daluminium

1. Acarbonate ions are oxidised to carbon dioxide
2. Bthe hydrated $Al^{3+}$ ion releases $H^+$ ions which react with the carbonate
3. Caluminium chloride decomposes releasing chlorine
4. Dsodium carbonate decomposes as it dissolves

1. Areduces the carbohydrate to carbon
2. Breacts with the cellulose to form a black sulphate
3. Cburns the paper by releasing heat only
4. Dremoves the elements of water from the carbohydrate, leaving carbon

1. Asilicon, a metalloid semiconductor
2. Bsulphur, a simple molecular element
3. Csodium, the first element in the period
4. Daluminium

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1. Ahaving a small ionic radius together with a high charge, giving a high charge density
2. Bhaving a structure with no coordinated water molecules present around it at all
3. Chaving a considerably larger ionic radius than the Na+ ion has overall, on the whole
4. Dhaving a noticeably lower ionic charge than the Na+ ion has overall, on the whole

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1. Aconverted directly into sulphur dioxide gas only, nothing else
2. Bleft completely unreacted as black carbon sitting on the paper surface
3. Coxidised further to carbon dioxide by the hot concentrated acid
4. Dreduced back into the original carbohydrate structure it started as

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1. Astructural isomerism
2. Bpositional isomerism
3. Ccis-trans isomerism
4. Doptical isomerism

1. Aa ketone
2. Ban aldehyde
3. Ca carboxylic acid
4. Dan alkene

1. Aamphoteric
2. Bneutral
3. Cacidic only
4. Dbasic only

1. Aa precipitate of sodium chloride
2. Bhydrogen gas and the sodium salt of Z
3. Coxygen gas and water
4. Dno reaction, because Z is chemically neutral

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1. A-Cl and -COCl groups, with steamy fumes of HCl given off
2. B-NH2 groups only, with oxygen gas given off instead of hydrogen chloride
3. C-OCH3 groups only, with water vapour given off instead of hydrogen chloride
4. D-Br and -COBr groups only, with no gas at all given off in the process

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1. Aimmediate and permanent immunity to the underlying disease being treated
2. Bcomplete and permanent loss of the drug's own chemical activity entirely
3. Ctoxic side effects as the drug accumulates or is metabolised in the body
4. Dspontaneous, chemically unexplained conversion of Z into pure water alone

1. Anon-superimposable mirror images
2. Bidentical structures with different names
3. Cstructures differing only in the position of a double bond
4. Dstructures with different molecular formulae

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1. Aamide
2. Bamine salt
3. Cester
4. Damino acid

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1. Ahydroxyl and carbon to carbon double bond
2. Bester and hydroxyl
3. Cketone and alkene
4. Dcarboxylic acid and alkene

1. Aan ionic sodium alkoxide
2. Ba smaller molecule than cholesterol
3. Ca compound containing a double bond
4. Da gas at room temperature

1. Ahydrolysis
2. Boxidation
3. Celectrophilic addition
4. Dreduction

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1. Aelectrophilic addition, forming a colourless dibromide
2. Bfree-radical substitution, requiring ultraviolet light
3. Cnucleophilic addition, forming an alcohol
4. Delectrophilic substitution, releasing hydrogen bromide gas

1. Areduced to a single carbon-carbon bond with no ring opening at all occurring
2. Bhydrolysed to give two separate alcohol groups only, with the ring intact
3. Coxidatively cleaved, breaking open the ring to form carbonyl and carboxyl fragments
4. Dsubstituted by a single hydroxyl group without any ring cleavage occurring

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1. AR-OH + Na -> R-Na + H2O
2. B2R-OH + Na -> R2O + H2 + NaOH
3. CR-OH + 2Na -> R-ONa2 + H2
4. D2R-OH + 2Na -> 2R-ONa + H2

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1. Aionic polymerisation
2. Bcondensation polymerisation
3. Caddition polymerisation
4. Dfree radical polymerisation

1. Aa diol and a dicarboxylic acid
2. Btwo different alkenes
3. Can amino acid and an alcohol
4. Da diamine and a dicarboxylic acid

1. Athe polymer simply dissolves in the alkali
2. Bthe polymer is oxidised by hydroxide ions
3. Cthe hydrogen bonds between the chains are broken
4. Dthe amide links are hydrolysed, breaking the chains

1. Aidentical in polarity to a typical addition polymer of the same size
2. Bnon-polar overall, due to its long, purely hydrocarbon chain backbone
3. Cmore hydrophilic, because it contains polar amide or ester groups
4. Dmore hydrophobic overall, because it has only a plain carbon backbone

1. Ahave weaker covalent bonds throughout the whole carbon backbone
2. Bcontain hydrolysable linkages, such as amide or ester groups
3. Ccontain only single carbon-to-carbon bonds throughout
4. Dare always more soluble in non-polar organic solvents

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1. Aform hydrogen bonds that hold neighbouring chains together while still letting them stretch and slide
2. Bare ionic in nature and repel each other, so the chains stay rigid and brittle
3. Cform permanent covalent crosslinks between the neighbouring chains
4. Dprevent any interaction at all between the neighbouring chains

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1. Apurely inorganic polymers with no carbon backbone
2. Bpolyesters containing only ester linkages, not amide ones
3. Cpolyamides containing amide (-CONH-) linkages
4. Daddition polymers made from exactly the same monomer

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1. Aincrease the solubility of the sample in water
2. Bkeep the detector at room temperature
3. Ckeep the components volatile so that retention times are reproducible
4. Dprevent the carrier gas from escaping

1. Acarbon monoxide only
2. Bsulphur dioxide and nitrogen oxides
3. Chydrogen chloride and dioxins
4. Dmethane and ammonia

1. A$K_3FeO_4$
2. B$K_2Fe_2O_5$
3. C$K_2FeO_4$
4. D$KFeO_2$

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1. Aare separated purely by molecular size, passing through a fine physical sieve
2. Breact chemically with the inert carrier gas itself at different rates
3. Cpartition differently between the gas mobile phase and the liquid stationary phase
4. Dcarry different electrical charges that migrate at different rates in an applied field

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1. Ameasure the pH of a solution
2. Btest blood-alcohol levels
3. Cdetermine the melting point of a solid
4. Dtitrate an acid against a base

1. Aanalyse the composition of petroleum fractions
2. Bdetermine the empirical formula of an unknown compound
3. Cprecipitate heavy metal ions out of waste water samples
4. Dmeasure the boiling point of a single pure liquid

1. Aconvert the surrounding, non-radioactive soil directly into usable fuel
2. Bneutralise itself completely and safely within just a few days of burial
3. Cleak radiation and contaminate groundwater and soil over very long half-lives
4. Dimmediately explode on contact with the moisture present in the surrounding soil

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1. A1.0 : 1.0 : 1.0
2. B2.0 : 1.0 : 4.0
3. C0.51 : 1.01 : 2.02
4. D1.01 : 0.51 : 2.02

1. Athe complex is always tetrahedral in shape
2. Bthe ligand field splitting is large so the electrons pair up in the lower orbitals
3. Cthe ligand field splitting is small so the electrons remain unpaired
4. Dthe central metal ion has no d electrons

1. Aare oxidised by the water to $Cu^{2+}$
2. Bare reduced by the sulphate ions
3. Cform a blue complex with water molecules
4. Ddisproportionate into $Cu^{2+}$ ions and copper metal

1. A0.05
2. B4.0
3. C20
4. D25

1. Athe ligand field splitting is small, so the electrons occupy all five d orbitals singly before any pairing
2. Bthere are no unpaired electrons present anywhere in the complex at all
3. Cthe ligand attached is always a strong-field ligand, such as cyanide
4. Dthe ligand field splitting is large, so the electrons pair up first in the lower orbitals

1. Aa brown precipitate consisting of solid copper metal only
2. Bdeep blue solution containing a tetraamminecopper(II) complex
3. Ca green solution containing dissolved copper(II) chloride salt
4. Da colourless solution containing only dissolved Cu+ ions in it

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1. Ano measurable contamination at all, since the soil filters out every single pollutant
2. Btoxic heavy metals and disease-causing microorganisms leached from the waste
3. Can unusually high concentration of dissolved oxygen only, and nothing else at all
4. Donly harmless mineral salts leached naturally from the surrounding soil layers

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1. Aadd even more waste to the landfill site so as to dilute the existing contamination there further
2. Btreat the water (e.g. filtration and disinfection) and site new boreholes further from the landfill
3. Cdrink the borehole water without any treatment at all, since the soil naturally purifies it completely
4. Dincrease the depth of the landfill site only, while leaving the borehole itself completely unchanged

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1. Anon-volatile in nature, so that it never evaporates away during the whole process
2. Bchemically reactive with the solute itself, so that it forms an entirely new compound
3. Cfully miscible with the original solvent used throughout the whole extraction process
4. Dimmiscible with the original solvent and dissolve the solute much better than it

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