Chemistry 9701/12 May/June 2020: question paper and mark scheme

Question

In which carbon allotrope are all electrons localised? A buckminsterfullerene B diamond C graphite D graphene

Question

A copper ore contains 3.00% of copper carbonate, CuCO3, by mass. Which mass of copper would be obtained from 1 tonne of the ore? A 1.91 kg B 3.71 kg C 15.4 kg D 58.4 kg

Question

The catalysed formation of ammonia by the Haber process can be represented by the equation shown. N2(g) + 3H2(g) 2NH3(g) ∆H = –92 kJ mol–1 Which change in conditions will increase both the rate of formation and the equilibrium yield of ammonia? A decrease in the temperature B increase in the temperature C increase in the pressure D increase in the surface area of the catalyst

Question

Solid sulfur consists of S8 molecules. Which equation represents the standard enthalpy of atomisation of sulfur? A 1 S (s) 8 8 → S(g) B 1 S (g) 8 8 → S(g) C S8(s) → 8S(g) D S8(g) → 8S(g)

Question

In this question you should use changes in oxidation numbers to balance a chemical equation. The following reaction occurs when MnO2 is warmed with dilute H2SO4. a MnO2 + b H+ → c Mn2+ + d MnO4– + e H2O What is the ratio of c : d in the correctly balanced equation? A 1:1 B 1:2 C 2:3 D 3:2

Question

In this question you should assume air contains 21% oxygen. What is the minimum volume of air required to ensure complete combustion of 10 cm3 of butane gas, under room conditions? A 14 cm3 B 27 cm3 C 65 cm3 D 310 cm3

Question

When aqueous bromine is shaken with cyclohexane and allowed to stand, two layers form. The top cyclohexane layer is coloured and the bottom aqueous layer is almost colourless. What is the most likely explanation for this observation? A Bromine is reduced to bromide ions in the bottom layer. B Bromine molecules are non-polar. C Bromine reacts with water but cannot react with cyclohexane. D The product of the reaction between bromine and cyclohexane is coloured.

Question

In which change are only temporary dipole-induced dipole forces overcome? A C2H5OH(l) → C2H5OH(g) B H2O(s) → H2O(l) C O2(s) → O2(l) D C4H10(l) → C4H10(s)

Question

The complete combustion of 2 moles of an alkane produces 400 dm3 of carbon dioxide measured at 301 K and 1 × 105 Pa. Carbon dioxide can be assumed to behave as an ideal gas under these conditions. What is the formula of the alkane? A C8H18 B C16H34 C C20H42 D C40H82

Question

In which reaction does an element undergo the largest change in oxidation number? A Cl 2 + 2OH– → OCl – + Cl – + H2O B 3Cl 2 + 6OH– → Cl O3– + 5Cl – + 3H2O C Cr2O72– + 6Fe2+ + 14H+ → 2Cr3+ + 6Fe3+ + 7H2O D 3MnO42– + 4H+ → MnO2 + 2MnO4– + 2H2O

Question

PCl 5 decomposes as shown. PCl 5(g) PCl 3(g) + Cl 2(g) 1.0 mol of PCl 5(g), 1.0 mol of PCl 3(g) and 1.0 mol of Cl 2(g) are placed in a container of volume 1 dm3 at 250 °C and allowed to reach equilibrium. At this temperature, the equilibrium mixture contains 1.8 moles of PCl 3. What is the value of Kc at 250 °C? A 1 B 1.8 C 9 D 16.2

Question

The fifth to eighth ionisation energies of four elements in Period 3 of the Periodic Table are shown. Which row refers to chlorine? ionisation energies / kJ mol–1 fifth sixth seventh eighth A 6280 21 200 25 900 30 500 B 6990 8 490 27 100 31 700 C 6540 9 330 11 000 33 600 D 7240 8 790 12 000 13 800

Question

Magnesium nitrate, Mg(NO3)2, decomposes when heated to give a white solid and a mixture of gases. One of the gases released is an oxide of nitrogen, X. 7.4 g of anhydrous magnesium nitrate is heated until no further reaction takes place. What mass of X is produced? A 1.5 g B 2.3 g C 3.0 g D 4.6 g

Question

Which statement explains why iodine is less volatile than chlorine? A Chlorine is more electronegative than iodine and so has more repulsion between its molecules. B The greater number of electrons in iodine leads to larger temporary dipole-induced dipole forces. C The I–I bond energy is smaller than the Cl –Cl bond energy. D The iodine molecules have stronger permanent dipole-permanent dipole forces.

Question

Ammonium carbonate is a crystalline solid. On gentle warming a reaction occurs, forming ammonia as one product. How are the carbonate ions behaving during this reaction? A Brønsted-Lowry acid B Brønsted-Lowry base C oxidising agent D reducing agent

Question

One molecule of an oxide of element Z reacts with six molecules of water to produce an acidic compound. What is element Z? A aluminium B phosphorus C silicon D sulfur

Question

Which property shows an increase from magnesium to barium? A the first ionisation energy of the elements B the oxidising power of the metals C the solubility of the hydroxides D the solubility of the sulfates

Question

A test-tube of HBr(g) and a separate test-tube of HI(g) are heated to the same temperature. Which combination of observations is possible? test-tube of HBr(g) test-tube of HI(g) A a brown vapour appears no change B a purple vapour appears no change C no change a brown vapour appears D no change a purple vapour appears

Question

Most modern cars are fitted with catalytic converters in the exhaust system. Which three gases are removed by a catalytic converter? A carbon monoxide, hydrocarbons, nitrogen oxides B carbon monoxide, carbon dioxide, nitrogen oxides C carbon monoxide, nitrogen oxides, sulfur dioxide D hydrocarbons, nitrogen oxides, sulfur dioxide

Question

Compound X is shown. compound X CO2H OH X is treated separately with NaOH(aq) and LiAl H4 to give Y and Z. CO2H NaOH(aq) LiAl H4 Y Z OH What are Y and Z? Y Z CO2Na CH2OH A OH OH CO2Na CO2H B OH OH CO2Na CH2OH C ONa OH CO2Na CO2H D ONa OH

Question

The table shows the molecular formulae of three molecules P, Q and R. None of the molecules are cyclic. molecule molecular formula P CH4O Q CH2O2 R CH2O Which molecules show a strong absorption between 1610 cm–1 and 1750 cm–1 in their infra-red spectra? A Q only B R only C Q and R only D P, Q and R

Question

Which row correctly shows the type of mechanism of each of the two reactions? C2H5Br + KCN CH3COCH3 + HCN A electrophilic substitution electrophilic addition B electrophilic substitution nucleophilic addition C nucleophilic substitution electrophilic addition D nucleophilic substitution nucleophilic addition

Question

Ester X is shown. ester X CH3CO2(CH2)7CH3 Ester X is hydrolysed using aqueous sodium hydroxide. What is the molecular formula of one of the products? A C2H4O2 B C2H3O2Na C C8H16O D C8H17O2Na

Question

Which reagent could be used to distinguish between propane-1,2-diol and ethane-1,2-diol? A alkaline aqueous iodine B aqueous acidified dichromate(VI) C ethanol and a few drops of concentrated sulfuric acid D sodium metal

Question

Which substance forms propanoic acid as one of the products when it reacts with hot concentrated acidified potassium manganate(VII)? A but-1-ene B but-2-ene C 2-methylpropene D 2-methylbut-1-ene

Question

The structure of damascenone is shown. damascenone O Including damascenone, how many stereoisomers exist with this structural formula? A 1 B 2 C 4 D 8

Question

How many isomeric esters have the molecular formula C4H8O2? A 2 B 3 C 4 D 5

Question

Ethene reacts with aqueous bromine to give two products, CH2BrCH2Br and CH2BrCH2OH. Which statement about these products is correct? A Both products are obtained in this reaction by nucleophilic substitution. B Both products are obtained in this reaction by nucleophilic addition. C Both products can be hydrolysed to form the same organic compound. D Both products can form hydrogen bonds with water.

Question

PVC is used as a packaging material. What holds the different polymer strands together in a piece of solid PVC? A covalent bonds B hydrogen bonds C ionic bonds D van der Waals’ forces

Question

The diagram shows the structure of buta-1,3-diene. buta-1,3-diene H H C C H H C C H H The addition reaction between buta-1,3-diene and two molecules of hydrogen bromide can produce three structurally isomeric products. How many of these products have at least one chiral centre? A 0 B 1 C 2 D 3 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

Scientists are trying to synthesise a new element with proton number 119. The element is predicted to be a Group 1 element in Period 8 of the Periodic Table. Which predictions are likely to be correct about this element? 1 The outermost occupied orbital of one atom of this element will be an s orbital. 2 The atomic radius will be the largest of the seven elements in Group 1. 3 It will have a greater first ionisation energy than element 118.

Question

Which reactions would have the reaction profile shown? energy progress of reaction 1 NaOH + HCl → NaCl + H2O 2 CaCO3 → CaO + CO2 3 2MgO → 2Mg + O2 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 factors can lead to an increase in the rate of a reaction? 1 a lower activation energy 2 an increase in temperature 3 an increase in the concentration of a reactant

Question

Sodium and fluorine are both reactive elements. Two atoms are described. F Na atomic number 9 11 nucleon number 19 23 Which statements about these two atoms, and the ions they can form, are correct? 1 One Na atom has two more protons than one F– ion. 2 One Na atom has two more neutrons than one F atom. 3 One Na+ ion has the same number of electrons as one F– ion.

Question

In the atmosphere, which transformations can involve sulfur dioxide as either a reagent or a catalyst? 1 NO2 to NO 2 NO to NO2 3 CO to CO2

Question

The bond ……P…… of the HBr molecule is ……Q…… than that of the HI molecule. Which pairs of words correctly complete the above sentence? P Q 1 energy greater 2 length less 3 polarity greater

Question

Compound X has the structure shown. compound X OH O Which statements about compound X are correct? 1 X will decolourise cold, acidified KMnO4(aq). 2 X gives an orange precipitate with 2,4-DNPH reagent. 3 X does not react with Tollens’ reagent.

Question

Propanal reacts with hydrogen cyanide. Which absorptions are present in the infra-red spectrum of the product? 1 a weak absorption in the range 2200–2250 cm–1 2 a strong absorption in the range 3200–3600 cm–1 3 a strong absorption in the range 1040–1300 cm–1

Question

Which alcohols cannot be dehydrated to form alkenes? 1 CH3OH 2 (CH3)3COH 3 CH3CH(OH)CH3 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

A reaction mechanism is shown. H 2C CH2 H 2C CH2 H 2C CH2 H 2C CH2 + Br – H 2C C Br H 2C C H H OH HO– Which statements about this reaction are correct? 1 Heterolytic bond fission occurs. 2 It is a substitution reaction. 3 OH– behaves as an electrophile.