Chemistry 0620/23 October/November 2024: question paper and mark scheme

Question

A sample of ethanol is left in an open beaker at room temperature. After 24 hours, no ethanol remains in the beaker. What has happened to the ethanol? A It has boiled. B It has condensed. C It has evaporated. D It has frozen.

Question

A gas is in a sealed container with a fixed volume. Which statements describe what happens to the molecules in the gas when the temperature is increased? 1 They move more slowly. 2 They collide with the walls of the container more frequently. 3 They collide with the walls of the container with less force. 4 They have greater kinetic energy. A 1 and 3 B 1 and 4 C 2 and 3 D 2 and 4

Question

What happens when sodium atoms combine with chlorine atoms to form sodium chloride? A Sodium atoms each gain one electron, and chlorine atoms each lose one electron. B Sodium atoms each lose one electron, and chlorine atoms each gain one electron. C Sodium atoms and chlorine atoms share one electron with each other. D Sodium atoms and chlorine atoms share two electrons with each other.

Question

The table shows some properties of four substances. electrical conductivity electrical conductivity substance melting point when solid when molten 1 high poor poor 2 high poor good 3 low poor poor 4 high good good Which substances are ionic? A 1, 3 and 4 B 1 and 3 only C 2 and 4 D 2 only

Question

Which statement about methane is correct? A In methane, positive hydrogen ions are attracted to negative carbon ions. B In methane, electrons are shared between carbon atoms and hydrogen atoms. C Methane has a high boiling point. D Methane is a good conductor of electricity.

Question

A sample of iridium has a relative atomic mass of 192.29. The sample contains two isotopes only. 64.50% of the sample is 193Ir. What is the other isotope in the sample? 189 190 191 192 A Ir B Ir C Ir D Ir

Question

Ammonium iron(III) citrate contains in its formula: ● more than one ammonium ion ● one iron ion ● two C6H4O74– ions. What is the formula of ammonium iron(III) citrate? A (NH4)4Fe(C6H4O7)2 B (NH4)5Fe(C6H4O7)2 C (NH4)6Fe(C6H4O7)2 D (NH4)7Fe(C6H4O7)2

Question

Silicon(IV) oxide reacts with chlorine and carbon to form liquid silicon( IV) chloride, SiCl 4, and carbon dioxide gas. If the reaction is carried out at r.t.p., which symbol equation represents this reaction? A SiO2(l) + 2Cl 2(g) + C(s) → SiCl 4(l) + CO2(g) B SiO2(l) + 2Cl 2(g) + C(g) → SiCl 4(l) + CO2(g) C SiO2(s) + 2Cl 2(g) + C(s) → SiCl 4(g) + CO2(g) D SiO2(s) + 2Cl 2(g) + C(s) → SiCl 4(l) + CO2(g)

Question

The structure of ethene is shown. H H C C H H How many hydrogen atoms and how many carbon atoms are in one mole of ethene? hydrogen atoms carbon atoms A 2.4 × 1024 1.2 × 1024 B 2.4 × 1024 6.0 × 1023 C 6.0 × 1023 1.2 × 1022 D 6.0 × 1023 6.0 × 1023

Question

A known volume and concentration of aqueous sodium hydroxide is titrated against dilute hydrochloric acid. The volume of dilute hydrochloric acid needed to exactly neutralise the sodium hydroxide is measured. Five calculation steps are shown. 1 Calculate the amount of hydrochloric acid in moles. 2 Calculate the relative formula mass of hydrochloric acid. 3 Calculate the concentration of hydrochloric acid in g / dm3. 4 Calculate the amount of sodium hydroxide in moles. 5 Calculate the concentration of hydrochloric acid in mol / dm3. What is the order of these steps to calculate the concentration of the hydrochloric acid in g / dm3? A 1→4→3→5→2 B 1→2→4→5→3 C 4→1→5→2→3 D 4→2→1→3→5

Question

Two different substances are electrolysed using inert electrodes in two separate experiments. Hydrogen is produced in both experiments. Which row identifies the two substances and the electrode at which hydrogen is produced? substance 1 substance 2 electrode A molten sodium chloride aqueous sodium chloride anode B molten sodium chloride aqueous sodium chloride cathode C dilute sulfuric acid concentrated hydrochloric acid anode D dilute sulfuric acid concentrated hydrochloric acid cathode

Question

Aqueous copper(II) sulfate can be electrolysed using either carbon electrodes or copper electrodes. Which statement describes what happens at the positive electrode? A Copper is deposited if the electrode is made from carbon. B Copper is deposited if the electrode is made from copper. C Oxygen gas is produced if the electrode is made from carbon. D Oxygen gas is produced if the electrode is made from copper.

Question

Which statement about a hydrogen–oxygen fuel cell is not correct? A Chemical energy is converted into electrical energy. B Hydrogen is oxidised. C The reaction that takes place is endothermic. D Water is the only chemical product.

Question

Which reaction pathway diagram is correctly labelled? A B Ea Ea 'H energy energy reactants reactants 'H products products progress of reaction progress of reaction C D 'H Ea energy energy reactants reactants Ea products 'H products progress of reaction progress of reaction

Question

Which row describes a reaction where the overall energy change is exothermic? energy needed for energy released by temperature of breaking bonds / kJ forming bonds / kJ the surroundings A 600 300 decreases B 600 1200 decreases C 900 300 increases D 900 1200 increases

Question

Which process involves a physical change only? A heating calcium carbonate strongly B burning wood C melting an ice cube D mixing an acid and a base

Question

In the Haber process, an equilibrium is established. N2(g) + 3H2(g) 2NH3(g) The forward reaction is exothermic. Which change to the reaction conditions will move the position of equilibrium to the left? A decreasing the pressure by 100 atm B decreasing the temperature by 100 °C C adding more nitrogen gas to the mixture D removing the iron catalyst

Question

The flow chart shows some properties of a metal oxide. reaction with reaction with water + salt metal oxide water + salt HCl (aq) NaOH(aq) reduction component of brass What is the metal oxide? A aluminium oxide B copper(II) oxide C iron(III) oxide D zinc oxide

Question

Which statement about reactants in redox reactions is correct? A An oxidising agent donates electrons, and a reducing agent accepts electrons. B When one element gains electrons, the oxidation number of a different element increases. C When the oxidation number of one element increases, a different element gains oxygen. D When the oxidation number of one element increases, a different element loses electrons.

Question

Aluminium is extracted from aluminium oxide by electrolysis. The ionic half-equation for the reaction at one of the electrodes is shown. Al 3+ + 3e– → Al Which row describes the change in oxidation number of the aluminium and the type of reaction at this electrode? change in oxidation type of reaction number of aluminium A decrease reduction B decrease oxidation C increase reduction D increase oxidation

Question

Which statement about dilute hydrochloric acid is correct? A It is a strong acid as it fully dissociates. B It is a strong acid as it partially dissociates. C It is a weak acid as it fully dissociates. D It is a weak acid as it partially dissociates.

Question

Which row describes and gives the formula of hydrated copper( II) sulfate? description of formula of hydrated copper(II) sulfate hydrated copper(II) sulfate A aqueous copper(II) sulfate CuSO4•5H2O B aqueous copper(II) sulfate CuSO4(aq) C copper(II) sulfate chemically CuSO4(aq) combined with water molecules D copper(II) sulfate chemically CuSO4•5H2O combined with water molecules

Question

The equations for three reactions are shown. 1 Pb(NO3)2(aq) + 2KI(aq) → PbI2(s) + 2KNO3(aq) 2 2AgNO3(aq) + CuI2(aq) → Cu(NO3)2(aq) + 2AgI(s) 3 CuO(s) + H2SO4(aq) → CuSO4(aq) + H2O(l) Which reactions are suitable for making a salt by precipitation? A 1 and 2 only B 1 and 3 only C 2 and 3 only D 1, 2 and 3

Question

Acidified potassium dichromate(VI), K2Cr2O7, is used to oxidise ethanol, C2H5OH. The ionic equation for the reaction is shown. 3C2H5OH + 2Cr2O72– + 16H+ → 3CH3COOH + 4Cr3+ + 11H2O Which properties of transition elements are shown by chromium in this reaction? variable acts as oxidation a catalyst number A B C D

Question

Which statements describe the Periodic Table? 1 The elements are arranged in order of their nucleon number. 2 The elements are arranged in order of their proton number. 3 It is used to predict the properties of elements. A 1 and 3 B 1 only C 2 and 3 D 2 only

Question

Which row shows the correct order of reactivity of the four named metals? most reactive least reactive A magnesium copper zinc silver B magnesium zinc copper silver C silver copper zinc magnesium D silver zinc copper magnesium

Question

Four iron nails are added to four different metal sulfate solutions. In which solution does a displacement reaction occur? A copper(II) sulfate B magnesium sulfate C sodium sulfate D zinc sulfate

Question

A fertiliser contains ammonium nitrate and potassium phosphate. Why is the fertiliser described as an NPK fertiliser? A It provides nitrogen, which is an essential element for improved plant growth. B It contains the element oxygen, which neutralises acidic soil. C It contains the elements nitrogen and phosphorus. D It provides the three main elements needed for improved plant growth.

Question

What are the approximate percentages of oxygen and nitrogen in clean, dry air? percentage percentage of oxygen of nitrogen A 19 80 B 21 78 C 80 19 D 78 21

Question

Which compounds have similar chemical properties? A butanol and butanoic acid B ethane and ethene C methane and butane D propene and propanol

Question

Four statements about organic compounds P, Q, R and S are listed. P is a saturated hydrocarbon. The formula of Q is CH3CH3. A molecule of R contains only one oxygen atom. Compound S is a carboxylic acid. Which statement about these compounds is correct? A P and Q are members of different homologous series. B P and S are members of the same homologous series. C Q and S are members of the same homologous series. D Q, R and S are all members of different homologous series.

Question

The structure of an organic compound is shown. H H H C C Cl H H What is the name of the compound? A chloroethane B chloroethene C chloroethanol D chloroethanoic acid

Question

Which statement about the manufacture of ethene from larger alkane molecules is correct? A A low temperature is required. B The process is called cracking. C The process requires an excess of oxygen. D Water is also a product.

Question

Which processes are used to make ethanoic acid? 1 heating ethanol with acidified aqueous potassium manganate(VII) 2 bacterial oxidation of ethanol 3 distilling ethanol using a fractionating column A 1 and 2 B 1 only C 2 and 3 D 3 only

Question

Which statement about propene, C3H6, is correct? A Propene reacts with bromine in the dark in a substitution reaction. B Propene reacts with steam in the presence of an alkaline catalyst, forming an alcohol. C Propene undergoes addition polymerisation, forming poly(ethene). D Propene undergoes an addition reaction to form an alkane.

Question

How many of each type of bond are present in ethanoic acid, CH3COOH? type of bond C–H C–C C=O A 3 1 1 B 3 0 2 C 4 0 2 D 4 1 2

Question

Which diagram represents the structure of a protein? O O O O A C C N N C C H H O O O O B C C O O C C C O O O H O H O D N C N C N C H O

Question

The chromatogram of substance S is shown. Some distances, W, X, Y and Z, are labelled on the diagram. solvent front substance S W X Y Z baseline solvent level How is the Rf value of substance S calculated? X W Y Y A B C D Y Z X W

Question

Some information about solid silver chloride and solid sodium chloride is shown. ● Silver chloride and sodium chloride do not dissolve in kerosene. ● Silver chloride is insoluble in water, but sodium chloride is soluble in water. ● The boiling point of silver chloride is 1547 °C and the boiling point of sodium chloride is 1413 °C. Which processes are used to separate a mixture of solid silver chloride and solid sodium chloride? A add kerosene, stir and then filter B add water, stir and then filter C add water, stir and then leave to crystallise D add water, stir and then perform fractional distillation

Question

Which statement describes how a flame test is done? A The tip of a clean wire is dipped into the substance and the wire is placed in a blue Bunsen burner flame. B The tip of a clean wire is dipped into the substance and the wire is placed in a yellow Bunsen burner flame. C A wooden splint is lit and is placed above a test-tube containing the gas being tested. D A wooden splint is lit, blown out and the glowing splint put into a test-tube of the gas being tested. The Periodic Table of Elements Group I II III IV V VI VII VIII 1 2 H He hydrogen helium Key 1 4 3 4 atomic number 5 6 7 8 9 10 Li Be atomic symbol B C N O F Ne lithium beryllium name boron carbon nitrogen oxygen fluorine neon 7 9 relative atomic mass 11 12 14 16 19 20 11 12 13 14 15 16 17 18 Na Mg Al Si P S Cl Ar sodium magnesium aluminium silicon phosphorus sulfur chlorine argon 23 24 27 28 31 32 35.5 40 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr potassium calcium scandium titanium vanadium chromium manganese iron cobalt nickel copper zinc gallium germanium arsenic selenium bromine krypton 39 40 45 48 51 52 55 56 59 59 64 65 70 73 75 79 80 84 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe rubidium strontium yttrium zirconium niobium molybdenum technetium ruthenium rhodium palladium silver cadmium indium tin antimony tellurium iodine xenon 16 85 88 89 91 93 96 – 101 103 106 108 112 115 119 122 128 127 131 55 56 57–71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 lanthanoids Cs Ba Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn caesium barium hafnium tantalum tungsten rhenium osmium iridium platinum gold mercury thallium lead bismuth polonium astatine radon 133 137 178 181 184 186 190 192 195 197 201 204 207 209 – – – 87 88 89–103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 actinoids Fr Ra Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og francium radium rutherfordium dubnium seaborgium bohrium hassium meitnerium darmstadtium roentgenium copernicium nihonium flerovium moscovium livermorium tennessine oganesson – – – – – – – – – – – – – – – – – 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 lanthanoids La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu lanthanum cerium praseodymium neodymium promethium samarium europium gadolinium terbium dysprosium holmium erbium thulium ytterbium lutetium 139 140 141 144 – 150 152 157 159 163 165 167 169 173 175 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 actinoids Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr actinium thorium protactinium uranium neptunium plutonium americium curium berkelium californium einsteinium fermium mendelevium nobelium lawrencium – 232 231 238 – – – – – – – – – – – The volume of one mole of any gas is 24 dm3 at room temperature and pressure (r.t.p.).