Chemistry Paper 2 June 2019

1. Aa shared pair of electrons between two metal atoms
2. Bthe attraction between induced dipoles in a metal
3. Cthe attraction between a lattice of positive ions and delocalised electrons
4. Dthe attraction between oppositely charged ions

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1. A86.5
2. B87.0
3. C87.7
4. D88.0

1. Athe two carbon atoms of the same molecule
2. Bthe $C=O$ bond and the $C-C$ bond
3. Cthe carbon atoms of adjacent molecules
4. Dan $N-H$ or $O-H$ bond and a lone pair on N or O

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1. AThe delocalised electrons that flow freely between its layers form a slippery liquid-like film.
2. BIts individual carbon atoms are unusually small and light, letting them slip past metal surfaces.
3. CIts very high melting point keeps it solid at all working temperatures, preventing surface wear.
4. DIts layers, held together only by weak van der Waals forces, slide easily over one another.

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1. A85
2. B86
3. C87
4. D88

1. Aone mole of a compound is broken into its gaseous atoms
2. Bone mole of a substance is completely burned in oxygen
3. Cone mole of gaseous atoms is formed from the element in its standard state
4. Done mole of gaseous ions is formed from gaseous atoms

1. Acombustion
2. Batomisation
3. Cneutralisation
4. Dformation

1. A$\Delta H_c(C_2H_5OH) - \Delta H_c(C) - \Delta H_c(H_2)$
2. B$2\Delta H_c(C) + 3\Delta H_c(H_2) - \Delta H_c(C_2H_5OH)$
3. C$\Delta H_c(C_2H_5OH) - 2\Delta H_c(C) - 3\Delta H_c(H_2)$
4. D$2\Delta H_c(C) + 3\Delta H_c(H_2) + \Delta H_c(C_2H_5OH)$

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1. A$\Sigma\Delta H_c^\theta(\text{reactants}) - \Delta H_c^\theta(\text{ethanol})$
2. B$\Delta H_c^\theta(\text{ethanol}) - \Sigma\Delta H_c^\theta(\text{reactants})$
3. C$\Sigma\Delta H_c^\theta(\text{reactants}) + \Delta H_c^\theta(\text{ethanol})$
4. D$\Delta H_c^\theta(\text{ethanol}) \div \Sigma\Delta H_c^\theta(\text{reactants})$

1. Aabove the reactants, because the reaction is exothermic.
2. Bbelow the reactants, because the reaction is exothermic.
3. Cabove the reactants, because the reaction is endothermic.
4. Dbelow the reactants, because the reaction is endothermic.

1. Ahas a giant covalent structure
2. Bis an ionic compound of low lattice energy
3. Cconsists of simple molecules held by weak van der Waals forces
4. Ddecomposes below room temperature

1. A$2Ge + 3Cl_2 \rightarrow Ge_2Cl_6$
2. B$Ge + 4Cl \rightarrow GeCl_4$
3. C$Ge + Cl_2 \rightarrow GeCl_2$
4. D$Ge + 2Cl_2 \rightarrow GeCl_4$

1. Ais a simple covalent molecule
2. Bhas a very high relative molecular mass
3. Cis a giant ionic solid with strong electrostatic forces
4. Dforms hydrogen bonds between its molecules

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1. Ait is an ionic compound whose weak, poorly-ordered lattice already melts long before it could boil.
2. Bit is a simple molecular substance held together by weak van der Waals forces between molecules.
3. Cchlorine atoms repel each other strongly, forcing the molecules apart at low temperatures.
4. Dthe covalent Ge-Cl bonds within each molecule are easily broken by a small amount of heat.

1. Aincreases then decreases sharply partway down the group.
2. Bgenerally decreases.
3. Cgenerally increases.
4. Dstays about the same throughout the group.

1. Aincreasing atomic size lowering the number of delocalised electrons per unit volume.
2. Bincreasing atomic size causing the metallic lattice to become ionic instead of metallic.
3. Cincreasing atomic size reducing the total number of valence electrons per atom.
4. Dincreasing atomic size raising the number of protons available to attract electrons.

1. Achlorinated ring products; free radical substitution
2. Bchlorinated ring products; electrophilic addition
3. C$C_6H_5CCl_3$; free radical substitution
4. D$C_6H_5CCl_3$; electrophilic substitution

1. Aconcentrated sulphuric acid
2. Baqueous sodium hydroxide
3. Ca halogen carrier such as $AlCl_3$
4. Dultraviolet light

1. Ahydrogen chloride reacts with methylbenzene
2. Bhydrogen chloride does not ionise in a non-polar solvent
3. Cmethylbenzene is itself a base
4. Dhydrogen chloride is insoluble in methylbenzene

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1. Aone or more chlorine atoms substituted directly onto the ring.
2. Ball six ring hydrogens replaced by hydroxyl groups.
3. Cthe methyl side chain completely removed and replaced by chlorine.
4. Da $CCl_3$ group substituted onto the side chain.

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1. Amethylbenzene is non-polar and cannot stabilise separated ions, so HCl does not ionise into $H^+$.
2. BHCl only ionises in the presence of a halogen-carrier catalyst such as $AlCl_3$.
3. Cmethylbenzene is far too dense and viscous for HCl gas to dissolve into it in any real amount.
4. Dmethylbenzene reacts with HCl to form a neutral organic salt before it can ionise.

1. Aa carbonyl group
2. Ba phenol group
3. Ca carboxylic acid group
4. Da carbon-carbon double bond

1. Aa ketone
2. Ban aldehyde
3. Can ether
4. Dan ester

1. A$HOOCCH_2CH(NH_3^+)COOH$
2. B$HOOCCH_2CH(NH_3^+)COO^-$
3. C$^-OOCCH_2CH(NH_2)COO^-$
4. D$HOOCCH_2CH(NH_2)COOH$

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1. Ahydroxyl group that is esterified directly by the dissolved bromine.
2. Bcarbon-carbon double bond or phenolic ring that reacts with the bromine.
3. Cether linkage that is cleaved, releasing free bromide ions into solution.
4. Dcarbonyl group that is oxidised by bromine water to a carboxylic acid.

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1. Athe amine group is protonated to $NH_3^+$ and both carboxylic acid groups remain un-ionised, giving an overall cation.
2. Bonly one carboxylic acid group ionises to $COO^-$ while the amine stays as $NH_2$, giving a singly charged anion.
3. Cboth carboxylic acid groups are deprotonated to $COO^-$ and the amine remains $NH_2$, giving an anion.
4. Dthe amine group is protonated to $NH_3^+$ and both carboxylic acid groups are also deprotonated, giving a neutral zwitterion.

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1. Acarbonyl (C=O)
2. Bester (-COO-)
3. Cether (C-O-C)
4. Dhydroxyl (-OH)

1. Ashifts the position of equilibrium
2. Bis used up during the reaction
3. Cis in the same phase as the reactants
4. Dis in a different phase from the reactants

1. Abonded to each other
2. Badjacent to each other, at 90°
3. Copposite each other, at 180°
4. Din the same plane as all four ammonia ligands

1. Athe manipulation of matter on a scale of 1 to 100 nm
2. Bthe use of catalysts in industrial processes
3. Cthe measurement of extremely small masses
4. Dthe study of very dilute solutions

1. Atheir high density provides enough thermal mass to absorb the heat released by the reaction, preventing it from reversing back to reactants.
2. Btheir large atomic radii create enough physical surface area on the metal to trap and hold gas molecules in place until a reaction occurs.
3. Ctheir high melting points let them remain solid at reaction temperatures while supplying the extra heat energy needed to start the reaction.
4. Dtheir partially filled d-orbitals let reactant molecules adsorb onto the metal surface and form weak temporary bonds, lowering the activation energy.

1. Aon opposite (180 degree) vertices of the octahedron.
2. Bon adjacent (90 degree) vertices of the octahedron.
3. Creplaced entirely by two extra ammonia ligands instead of chlorides.
4. Dboth bonded through nitrogen instead of chlorine.

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1. Aimproving the tensile strength of construction steel.
2. Bextending the shelf life of packaged food through UV-blocking coatings.
3. Ctargeted drug delivery to specific cells or tissues.
4. Dincreasing the fuel efficiency of combustion engines.

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