Chemistry 9701/11 May/June 2019: question paper and mark scheme

Question

The temperature of a sample of an inert gas is increased. What effect does this have on the number of molecules with the most probable energy and on the number of molecules with high energy? number of molecules with number of molecules the most probable energy with high energy A decreases decreases B decreases increases C increases decreases D increases increases

Question

A sample of element X is analysed using mass spectrometry. The mass spectrum obtained is shown. 56% 41% % abundance 3% 112 113 114 115 116 m/e What is the relative atomic mass of this sample of element X? A 113.7 B 114.0 C 114.2 D 114.4

Question

A washing powder contains sodium hydrogencarbonate, NaHCO3, as one of the ingredients. In a titration, a solution containing 1.00 g of this washing powder requires 7.15 cm3 of 0.100 mol dm–3 sulfuric acid for complete reaction. The sodium hydrogencarbonate is the only ingredient that reacts with the acid. What is the percentage by mass of sodium hydrogencarbonate in the washing powder? A 3.0% B 6.0% C 12.0% D 24.0%

Question

The outermost electron in an atom of neon occupies a particular orbital. Which row shows the relative energy and shape of this orbital? energy of orbital relative shape of orbital to other occupied orbitals A higher or equal B higher or equal C lower or equal D lower or equal

Question

In which species is there a lone pair of electrons? A CH3 B CH3+ C CH3– D CH4

Question

When an evacuated tube of volume 400 cm3 is filled with gas at 300 K and 101 kPa, the mass of the tube increases by 0.65 g. Assume the gas behaves as an ideal gas. What could be the identity of the gas? A argon B helium C krypton D neon

Question

Under which conditions will nitrogen behave most like an ideal gas? temperature pressure A low high B high low C low low D high high

Question

Two reactions and their enthalpy changes are shown. 2C(s) + 2H2(g) → C2H4(g) ∆H o = +52.2 kJ mol–1 C2H2(g) + H2(g) → C2H4(g) ∆H o = –175.8 kJ mol–1 These data can be used to calculate the enthalpy change for the reaction shown. 2C(s) + H2(g) → C2H2(g) ∆H o = X What is the value of X? A –228.0 kJ mol–1 B –123.6 kJ mol–1 C +123.6 kJ mol–1 D +228.0 kJ mol–1

Question

Ethanedioic acid, HO2CCO2H, can be oxidised by KMnO4 in dilute sulfuric acid. The products of this reaction are carbon dioxide, water, potassium sulfate and manganese(II) sulfate. In this reaction each ethanedioic acid molecule loses two electrons as it is oxidised. A half-equation for this process is shown. HO2CCO2H → 2CO2 + 2H+ + 2e– How many water molecules are produced when five ethanedioic acid molecules are oxidised by KMnO4 in dilute sulfuric acid? A 5 B 8 C 10 D 16

Question

Hydrogen iodide gas decomposes reversibly producing iodine vapour and hydrogen. 2HI(g) I2(g) + H2(g) ∆H = +12 kJ mol–1 The position of the equilibrium for this reaction may be altered by changing the external conditions. Which row correctly describes the change in position of equilibrium? effect of increasing effect of increasing the pressure the temperature A moves to the right moves to the right B moves to the right moves to the left C no change moves to the right D no change moves to the left

Question

The reaction between sulfur dioxide and oxygen is reversible. 2SO2(g) + O2(g) 2SO3(g) Kc = 280 mol–1 dm3 at 1000 K In an equilibrium mixture at 1000 K the sulfur trioxide concentration is 6.00 mol dm–3. The sulfur dioxide concentration is twice the oxygen concentration. What is the sulfur dioxide concentration? A 0.175 mol dm–3 B 0.254 mol dm–3 C 0.318 mol dm–3 D 0.636 mol dm–3 12 1.15 g of a metallic element needs 300 cm3 of oxygen for complete reaction, under room conditions, to form an oxide which contains O2– ions. What could be the identity of this metallic element? A calcium B magnesium C potassium D sodium

Question

In the question paper above.

Question

The relative melting points of four consecutive elements in the Periodic Table are shown in the graph. The elements all have proton numbers less than 20. Which element is in Group 16? A melting point / K B C 273 D proton number

Question

Substance X reacts with water. A gas is given off and the pH of the solution increases. The solution is then reacted with sulfuric acid and a white precipitate forms. What could be substance X? A barium B barium oxide C magnesium D magnesium oxide

Question

Solutions of 0.1 mol dm–3 Mg(NO3)2 and 0.1 mol dm–3 Ba(NO3)2 separately undergo a series of reactions using pure reagents. sodium carbonate excess HCl (aq) excess solution then boil NaOH(aq) Mg(NO3)2(aq) M N P sodium carbonate excess HCl (aq) excess solution then boil NaOH(aq) Ba(NO3)2(aq) Q R S M, N and P are magnesium compounds. Q, R and S are barium compounds. How many of M, N, P, Q, R and S are white precipitates? A 2 B 3 C 4 D 5

Question

Concentrated sulfuric acid is added to separate solid samples of sodium chloride, sodium bromide and sodium iodide. With which samples does sulfuric acid act as an oxidising agent? A sodium chloride only B sodium chloride and sodium bromide C sodium bromide and sodium iodide D sodium iodide only

Question

The reaction of bromine with warm NaOH(aq) produces products with the same oxidation numbers, in the same ratios, as the reaction of chlorine with hot NaOH(aq). In one reaction between bromine and warm NaOH(aq), 30.2 g of a product containing sodium, bromine and oxygen is produced. Which mass of NaOH has reacted? A 8.00 g B 10.2 g C 20.3 g D 48.0 g

Question

At 550 °C nitrogen dioxide reacts with unburnt hydrocarbon fragments such as CH3 in the catalytic converter of a motor vehicle. 4CH3 + 7NO2 → 3 21 N2 + 4CO2 + 6H2O Which row gives the energy change for this reaction and a possible reason for it? energy change reason why the reaction is endothermic of reaction or exothermic A endothermic chemical energy is converted to heat energy B endothermic the N≡N bond energy is very high C exothermic CO2 and H2O have negative values D exothermic double bonds are broken in NO2

Question

Which statement is correct? A Ammonia reacts with alkalis to form the ammonium ion. B Ammonium chloride contains ionic, covalent and co-ordinate bonds. C The ammonium ion reacts with acids to produce ammonia. D The bond angle in the ammonium ion is approximately 107°.

Question

The diagrams show two different compounds. O O 1 2 What is ● the total number of structural isomers, including compound 2, that could be formed by adding a second methyl group to the ring of compound 1, ● the number of π electrons in each compound? number of number of isomers π electrons A 3 2 B 3 4 C 5 2 D 5 4

Question

Which compound has the molecular formula C6H10O? A B C D O O O OH

Question

What is the structural formula of the major product when hydrogen bromide reacts with 2-methylbut-2-ene? A CH2BrCH(CH3)CH2CH3 B (CH3)2CBrCH2CH3 C (CH3)2CHCHBrCH3 D (CH3)2CHCH2CH2Br

Question

Which reaction is most likely to involve the formation of a positively charged intermediate? A 1-bromopentane and warm dilute NaOH(aq) B 1-bromo-2,2-dimethylpropane and warm dilute NaOH(aq) C 1-bromo-3-methylbutane and warm dilute NaOH(aq) D 2-bromo-2-methylbutane and warm dilute NaOH(aq)

Question

The infra-red spectrum of a substance with empirical formula C2H4O is shown. 100 transmittance 50 X Y 0 4000 3000 2000 1500 1000 500 –1 wavenumber / cm Which bonds are responsible for peak X and peak Y? peak X peak Y A C–H C=C B C–H C=O C O–H C=C D O–H C=O

Question

The structure of coniine is shown. coniine N CH2CH2CH3 H Coniine can be synthesised by reacting ammonia with a dibromo compound, X. NH3 + C8H16Br2 → coniine + 2HBr X What is the name of compound X? A 1,1-dibromo-2-propylcyclopentane B 1,2-dibromo-2-propylcyclopentane C 1,4-dibromooctane D 1,5-dibromooctane

Question

Structural isomerism and stereoisomerism should be considered when answering this question. 3-methylhexan-3-ol reacts with hot, concentrated sulfuric acid to form several isomeric compounds with the molecular formula C7H14. 3-methylhexan-3-ol HO How many isomeric compounds could be formed in this reaction? A 3 B 4 C 5 D 6

Question

An organic compound T undergoes the following reactions. ● T is oxidised by hot, acidified potassium manganate(VII). ● T reacts with sodium to give hydrogen. What could be compound T? A CH3CH2CH(OH)CH3 B CH3CH2CH2CHO C (CH3)3COH D CH3CH2COCH3

Question

Compound X is treated with two reagents successively, forming compound Z. X CHO a mild oxidising agent NaBH4 Y Z COCH3 What could be Z? A B C D CO2H CH2OH CH2OH CO2H CH(OH)CH3 CH(OH)CH3 CH(OH)CH3 CH(OH)CH3

Question

Which reagent may be used to distinguish between propanone and ethanol? A 2,4-dinitrophenylhydrazine B bromine water C Fehling’s reagent D Tollens’ reagent

Question

Which compound is chiral? A 1-chloro-3-methylbutane B 2-chloro-2-methylbutane C 2-chloro-3-methylbutane D 3-chloropentane 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

An atom of calcium-48 can form a 2+ ion. Which statements about this ion are correct? 1 It has 20 protons. 2 It has 28 neutrons. 3 It has 22 electrons.

Question

Four elements, W, X, Y and Z, have electronic configurations as shown. W X Y Z 2,4 2,6 2,8,2 2,8,8,1 Which formulae represent compounds that have boiling points below room temperature? 1 WX2 2 YX 3 Z2X

Question

Which statements about enthalpy changes are correct? 1 The enthalpy change of atomisation is always positive. 2 The enthalpy change when a C–C bond is broken is positive. 3 The enthalpy change of neutralisation of a weak acid is always negative.

Question

Vanadium and pepsin can both act as catalysts. Vanadium is a metal. Pepsin is an enzyme. Which statements are correct for both vanadium and pepsin? 1 They will speed up any chemical reaction. 2 They can lower the activation energy for a reaction. 3 They are not used up when they act as catalysts.

Question

Which oxides, when placed in cold water for one day, will react with the water? 1 MgO 2 Al 2O3 3 SiO2

Question

A mixture of magnesium carbonate and magnesium nitrate is heated strongly in a hard-glass test-tube. Which gases are formed? 1 carbon dioxide 2 nitrogen dioxide 3 oxygen

Question

Which statements about poly(alkene)s are correct? 1 Poly(alkene)s do not react with Br2(aq) in the dark. 2 Disposal of poly(alkene)s by combustion can produce harmful products. 3 Poly(alkene)s do not readily biodegrade. 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

Compound Y ● reacts with alkaline aqueous iodine to form a yellow precipitate ● changes the colour of warm, acidified potassium dichromate(VI) solution. What could be compound Y? OH 1 O 2 H 3 O

Question

Carboxylic acids can be made by several different reactions. Which statements are correct? 1 The acid hydrolysis of CH3CH2CN will make ethanoic acid. 2 The oxidation of CH3CH2CH2CH2OH will make butanoic acid. 3 The oxidation of CH3CH2CHO will make propanoic acid.

Question

Carboxylic acids react with alcohols to produce esters. Carboxylic acid X forms one ester only with molecular formula C5H10O2. What could X be? 1 ethanoic acid 2 propanoic acid 3 butanoic acid