Chemistry 9701/11 May/June 2021: question paper and mark scheme

Question

Which contains the largest number of hydrogen atoms? A 0.10 mol of pentane B 0.20 mol of but-2-ene C 1.00 mol of hydrogen molecules D 6.02 × 1023 hydrogen atoms

Question

In which pair of species do both species have only one unpaired p electron? A Ar+ and C– B B and Ti+ C F and Ga D Se– and Si–

Question

Phosphorus forms two chlorides. Phosphorus(III) chloride, PCl 3, is a covalent liquid. Phosphorus(V) chloride is an ionic solid. One of the ions present is [PCl 4]+. What is the shape of the PCl 3 molecule and the [PCl 4]+ ion? PCl 3 [PCl 4]+ A pyramidal square planar B pyramidal tetrahedral C tetrahedral square planar D trigonal planar tetrahedral

Question

is the standard enthalpy of formation of methane. is the standard enthalpy of combustion of carbon. is the standard enthalpy of combustion of hydrogen. CH4(g) + 2O2(g) CO2(g) + 2H2O(l) Which expression is equivalent to ? A – + B – 2 – C – + D + 2 –

Question

The diagram shows the Boltzmann distribution for the same gas at two different temperatures, T1 and T2. T1 T2 y 0 0 x What is plotted on the y-axis and which line represents the higher temperature? plotted on y-axis higher temperature A number of molecules T1 B number of molecules T2 C molecular energy T1 D molecular energy T2

Question

What is the minimum mass of oxygen required to ensure the complete combustion of 12 dm3 of propane measured under room conditions? A 60 g B 80 g C 120 g D 160 g

Question

Why is the first ionisation energy of oxygen less than that of nitrogen? A The nitrogen atom has its outer electron in a different subshell. B The nuclear charge on the oxygen atom is greater than that on the nitrogen atom. C The oxygen atom has a pair of electrons in one p orbital that repel one another. D There is more shielding in an oxygen atom.

Question

Which gas would behave most like an ideal gas under room conditions? A helium B nitrogen C ammonia D krypton

Question

When hydrogen iodide is reacted with concentrated sulfuric acid, several reactions occur, including: 8HI + H2SO4 → H2S + 4H2O + 4I2 Which row gives the change in oxidation number of iodine and of sulfur in this reaction? change in oxidation change in oxidation number of iodine number of sulfur A –1 +6 B –1 +8 C +1 –6 D +1 –8

Question

The diagram represents the Haber process for the manufacture of ammonia from nitrogen and hydrogen. heat exchanger N2 + H2 catalytic converter condenser NH3 What is the purpose of the heat exchanger? A to cool the incoming gas mixture to avoid overheating the catalyst B to cool the reaction products and separate the NH3 from unused N2 and H2 C to warm the incoming gas mixture and shift the equilibrium to give more NH3 D to warm the incoming gas mixture and speed up the reaction

Question

Which statement about catalysts is correct? A They change the reaction pathway by increasing the activation energy. B They increase the rate of reaction by lowering the enthalpy change of the reaction. C They increase the number of particles that have sufficient energy to react. D Heterogeneous catalysts are in the same state as the reactant.

Question

Element X is in Period 3. Element X forms a solid oxide Y. Y reacts with hot concentrated hydrochloric acid. Y reacts with hot aqueous sodium hydroxide to form a compound in which X is part of an anion. How many p electrons does one atom of X have in its outer shell? A 0 B 1 C 2 D 3

Question

The gaseous products of heating a mixture of Ca(OH)2 and NH4Cl are passed through solid CaO. A single gaseous product, W, is collected. A sample of W reacts with Cl 2(g) to produce two gases, X and Y. X is an element. Y is acidic. Y reacts with W to produce Z. What are X and Z? X Z A N2 CaCl 2 B N2 NH4Cl C O2 CaCl 2 D O2 NH4Cl

Question

Q is a mixture of a Group 2 oxide and a Group 2 sulfate. Q contains equal amounts of the two compounds. Q is shaken with water and the resulting mixture filtered; a solid residue is obtained. There is no reaction when the solid residue is shaken with HCl (aq). Shaking the filtrate with H2SO4(aq) produces a white precipitate. What could be Q? A BaO + BaSO4 B BaO + MgSO4 C MgO + BaSO4 D MgO + MgSO4

Question

Which substance will not be a product of the thermal decomposition of hydrated magnesium nitrate? A dinitrogen monoxide B magnesium oxide C oxygen D steam

Question

A 5 cm3 sample of 0.05 mol dm–3 sodium chloride is mixed with a 5 cm3 sample of 0.05 mol dm–3 potassium iodide. 10 cm3 of acidified 0.05 mol dm–3 silver nitrate is then added, followed by concentrated ammonia solution. What is seen after the addition of an excess of concentrated ammonia solution? A a cream precipitate B a white precipitate C a yellow precipitate D no precipitate

Question

The volatility of the Group 17 elements, chlorine, bromine and iodine, decreases down the group. What is responsible for this trend? A bond length in the halogen molecule B bond strength in the halogen molecule C electronegativity of the halogen atom D number of electrons in the halogen atom

Question

Acid rain is a dilute solution of sulfuric acid. Which pollutant also contributes to the formation of acid rain? A carbon monoxide B carbon dioxide C nitrogen dioxide D hydrocarbons

Question

R is an oxide of Period 3 element T. 5.00 g of R contains 2.50 g of T. What is T? A magnesium B aluminium C silicon D sulfur

Question

Bromoethane reacts with cyanide ions, producing propanenitrile. Which statement about the SN2 mechanism of this reaction is correct? A The lone pair of electrons on C of CN– attacks the carbon atom of the C–Br bond. B The lone pair of electrons on C of CN– attacks the carbocation formed when the C–Br bond breaks. C The lone pair of electrons on N of CN– attacks the carbon atom of the C–Br bond. D The lone pair of electrons on N of CN– attacks the carbocation formed when the C–Br bond breaks.

Question

Which compound would produce two different carboxylic acids when treated with hot, concentrated, acidified manganate(VII) ions? A B C D

Question

Which compound could show both cis-trans isomerism and optical isomerism? A B C D Cl Cl O Br Cl H H H Br Br Br C C Br Br C C C C C Br C C Br C C Cl C C I Br H I H Cl H Br H

Question

Limonene is a hydrocarbon found in the rind of citrus fruits. limonene What is the molecular formula of limonene? A C10H12 B C10H14 C C10H16 D C10H18

Question

The compound cetyl palmitate, C15H31CO2C16H33, is a waxy solid. Cetyl palmitate is heated under reflux with an excess of aqueous sodium hydroxide. Which products will be formed? A C15H31ONa and C16H33CO2Na B C15H31CO2Na and C16H33ONa C C15H31OH and C16H33CO2Na D C15H31CO2Na and C16H33OH

Question

When an organic compound is oxidised, any oxygen atom gained by the organic molecule is considered to be from a water molecule also producing 2H+ + 2e–. Any hydrogen atom lost may be considered to be lost as H+ + e–. These changes can be represented by the following two equations. H2O → [O] + 2H+ + 2e– [H] → H+ + e– Compound X is oxidised by heating under reflux with hot, acidified potassium dichromate(VI) for one hour. The half-equation for the reduction reaction is shown. Cr2O72– + 14H+ + 6e– → 2Cr3+ + 7H2O Under these conditions, one mole of potassium dichromate(VI) oxidises three moles of X. What could X be? A propanal B propan-1-ol C propan-1,2-diol D propan-1,3-diol

Question

Compound X has the empirical formula C2H4O. Its infra-red spectrum is shown. 100 transmittance / % 50 0 4000 3000 2000 1500 1000 500 –1 wavenumber / cm What could be the skeletal formula of compound X? A B C D OH O O O O O O H OH

Question

How many moles of hydrogen, H2, are evolved when an excess of sodium metal is added to one mole of citric acid? citric acid CO2H HO C CH2CO2H CH2CO2H A 0.5 B 1.5 C 2 D 4

Question

Which statement is correct for the reaction of carbonyl compounds with HCN? A The reaction is catalysed by concentrated H2SO4. B Pentan-2-one and HCN react to give a chiral product. C The reaction is a condensation reaction. D The reaction is nucleophilic substitution.

Question

The table describes four reactions of propene. Which row is correct? name of main reagent used organic product A aqueous bromine 2-bromopropane B cold acidified aqueous potassium manganate(VII) propane-1,3-diol C hydrogen chloride 2-chloropropane D steam propan-1-ol

Question

Butanoic acid is prepared from 1-bromopropane. This synthesis requires a sequence of two reactions. Which compound is prepared in the first stage of the synthesis? A 1-aminopropane B propan-1-ol C butanal D butanenitrile Section B For each of the questions in this section, one or more of the three numbered statements 1 to 3 may be correct. Decide whether each of the statements is or is not correct (you may find it helpful to put a tick against the statements that you consider to be correct). The responses A to D should be selected on the basis of A B C D 1, 2 and 3 1 and 2 2 and 3 1 only are only are only are is correct correct correct correct No other combination of statements is used as a correct response. Use of the Data Booklet may be appropriate for some questions.

Question

Ethanol combines with ethanoic acid to form ethyl ethanoate according to the following reaction. C2H5OH(I) + CH3CO2H(I) CH3CO2C2H5(I) + H2O(I) ∆H o = –6 kJ mol–1 9.2 g ethanol, 12 g ethanoic acid and 8.8 g ethyl ethanoate are mixed and allowed to stand at 298 K, until equilibrium is reached. (Mr: C2H5OH, 46; CH3CO2H, 60; CH3CO2C2H5, 88) The resulting equilibrium mixture is found to contain 4.8 g ethanoic acid. The experiment is repeated at 323 K. Which statements are correct? 1 There are 0.22 moles of ethyl ethanoate in the mixture at equilibrium at 298 K. 2 The equilibrium mixture at 323 K will contain more than 4.8 g of ethanoic acid. 3 If a small amount of water is added at the start of either experiment the value of Kc would not be affected.

Question

The diagram shows an incomplete energy profile diagram for a reaction. products enthalpy reactants progress of reaction Which reactions could this diagram refer to? 1 CaCO3(s) → CaO(s) + CO2(g) 2 H2(g) → 2H(g) 3 Cl –(aq) → Cl –(g) + aq

Question

A gaseous hydrocarbon has a density of 2.42 g dm–3 under room conditions. What could be the skeletal formula of this hydrocarbon? 1 2 3

Question

Which molecules contain at least one bond angle of 120°? 1 C2H4 2 PF5 3 NCl 3

Question

Which statements are correct going across Period 3 from sodium to chlorine? 1 The charge on the nucleus increases, pulling the electrons closer to it. 2 The radius of the most common ion of each element decreases. 3 The shielding caused by inner electrons decreases, so the outer electrons are pulled closer to the nucleus. The responses A to D should be selected on the basis of A B C D 1, 2 and 3 1 and 2 2 and 3 1 only are only are only are is correct correct correct correct No other combination of statements is used as a correct response.

Question

Which statements are correct? 1 Magnesium carbonate decomposes at a lower temperature than calcium carbonate. 2 Calcium hydroxide is more soluble in water than magnesium hydroxide. 3 Calcium is a stronger reducing agent than magnesium.

Question

Which statements are correct? 1 1,1-difluoroethane is less reactive than 1,1-dichloroethane. 2 1,1-difluoroethane is polar. 3 The C–F bond is stronger than the C–Cl bond.

Question

Which pairs of compounds may be distinguished by testing with alkaline aqueous iodine? 1 butanal and butanone 2 pentan-2-one and pentan-3-ol 3 propanone and propan-2-ol

Question

Which reactions have a coloured organic product? 1 ethanal + 2,4-dinitrophenylhydrazine reagent 2 ethanol + acidified potassium dichromate(VI) 3 ethene + cold dilute acidified potassium manganate(VII)

Question

Propanoic acid is reacted with an excess of lithium aluminium hydride. The organic product of this reaction is reacted with ethanoic acid in the presence of concentrated sulfuric acid, forming product X. What are major commercial uses of X? 1 fuel 2 solvent 3 flavouring