Chemistry 0620/12 May/June 2025: question paper and mark scheme

Question

Substance L melts at –7 °C and is a brown liquid at room temperature. What is the boiling point of pure L? A –77 °C B –7 °C to +7 °C C 59 °C D 107 °C to 117 °C

Question

Which row describes how the volume of a gas changes when its temperature is increased at constant pressure and when its pressure is increased at constant temperature? temperature is increased pressure is increased at constant pressure at constant temperature A volume decreases volume decreases B volume decreases volume increases C volume increases volume decreases D volume increases volume increases

Question

Nitrogen dioxide is a red-brown gas which is more dense than air. The diagram shows the arrangement of two gas jars which contain nitrogen dioxide and air separated with a glass plate. colourless air glass plate red-brown nitrogen dioxide The glass plate is removed, and the gas jars are left for 24 hours. Which diagram shows the gas jars after 24 hours? A B C D

Question

Which substance is a mixture of one element and one compound? A aqueous glucose B clean, dry air C oxygen dissolved in distilled water D stainless steel

Question

Which statement defines the atomic number of an element? A the group number of the element B the mass of one atom of the element C the number of particles in the nucleus of one atom of the element D the number of protons in the nucleus of one atom of the element

Question

What is different for isotopes of the same element? A nucleon number B number of electron shells C number of electrons in the outer electron shell D proton number

Question

When sodium chloride is formed from its elements, each chlorine atom ……1…… one ……2…… . Which words correctly complete gaps 1 and 2? 1 2 A gains electron B gains proton C loses electron D loses proton

Question

In the molecules CH4, HCl and H2O, which atoms use all of their outer shell electrons in bonding? A C and Cl B C and H C Cl and H D H and O

Question

Which substance has a giant covalent structure? A sodium chloride B ammonia C magnesium chloride D graphite

Question

The diagrams show the structures of four molecules. H H H H H O H H H O H C C H H C C H H C C C H H C C C H H C C H H C O H H H H H H H Which statement about these molecules is correct? A All four molecules have different molecular formulae. B All four molecules have the same molecular formula. C Only two molecules have the same molecular formula. D Only three molecules have the same molecular formula.

Question

The equation for the reaction of magnesium with oxygen is shown. 2Mg + O2 → 2MgO Which mass of oxygen reacts exactly with 6 g of magnesium? A 2g B 4g C 8g D 16 g

Question

The diagram shows a simple electrolytic cell for an electrolysis experiment. X + – Y Z Three parts of the electrolytic cell are labelled X, Y and Z. Which row shows the correct labels to replace X, Y and Z in the diagram? X Y Z A anode cathode aqueous salt B anode cathode solid salt C cathode anode aqueous salt D cathode anode solid salt

Question

Which equation represents the overall reaction that produces electricity in a hydrogen–oxygen fuel cell? A H2 + O2 → H2O2 B 2H2O → 2H2 + O2 C 2H2 + O2 → 2H2O D 2H2O2 → 2H2O + O2

Question

Which reaction pathway diagram shows the largest increase in the temperature of the surroundings? (The scale on the y-axis is the same in each diagram.) A B products products energy energy reactants reactants progress of reaction progress of reaction C D reactants reactants products energy energy products progress of reaction progress of reaction

Question

Which process involves a chemical change? A dissolving copper(II) sulfate B distilling ethanol C freezing water D neutralising copper(II) oxide

Question

The total volume of gas produced in two different experiments is measured against time. A graph of the results of the two experiments is shown. Which point shows the fastest rate of reaction? D experiment 2 experiment 1 B total volume of gas C A 0 0 time

Question

The equation for the reaction of sulfur dioxide with oxygen is shown. 2SO2 + O2 2SO3 What is meant by the symbol ? A redox reaction B reversible reaction C displacement reaction D thermal decomposition reaction

Question

Which reactions are redox reactions? 1 the incomplete combustion of propane 2 the rusting of iron 3 the reaction of aqueous chloride ions with acidified aqueous silver nitrate 4 the thermal decomposition of calcium carbonate A 1 and 2 B 1 and 3 C 2 and 4 D 3 and 4

Question

Which row describes an aqueous solution for the pH shown? pH description A 1 has a very high alkalinity B 5 is neutral C 9 turns universal indicator yellow D 14 contains OH– ions

Question

Which parts of the Periodic Table contain elements that only form basic oxides? A Group I and Period 3 B Group I only C Group VIII and Period 3 D Group VIII only

Question

Which statement about elements in the Periodic Table is correct? A Elements in the same group of the Periodic Table have the same electronic configuration. B The atoms of the elements in Group VII form ions with a charge equal to the number of outer shell electrons minus 8. C The metallic character of the elements increases from left to right across a period. D The Periodic Table is an arrangement of elements in order of increasing nucleon number.

Question

Which row identifies the trends in properties of the elements lithium to sodium to potassium? melting point density reactivity A decreasing increasing increasing B increasing increasing decreasing C increasing decreasing increasing D decreasing decreasing increasing

Question

Which statements about the halogens are correct? 1 They are all diatomic molecules. 2 They are all gases at room temperature and pressure. 3 The density of the elements increases down the group. 4 The reactivity of the elements increases down the group. A 1 and 2 B 1 and 3 C 2 and 4 D 3 and 4

Question

Zirconium is a transition element. What is a property of zirconium? A high density B does not conduct heat C forms white compounds only D low melting point

Question

Some gases exist as single atoms, are unreactive and have eight electrons in their outer electron shell. Which gases fit this description? 1 helium 2 argon 3 oxygen 4 krypton A 1, 2 and 4 B 1 and 3 C 2 and 4 only D 3 only

Question

Which statements about metals are correct? 1 Calcium reacts faster than magnesium with cold water. 2 Aluminium is more easily extracted than iron from its ore. 3 Copper reacts faster than iron with dilute hydrochloric acid. 4 Potassium and silver are both good conductors of electricity. A 1 and 2 B 1 and 4 C 2 and 3 D 3 and 4

Question

Four metals, P, Q, R and S, are separately reacted with dilute hydrochloric acid. The table shows the observation for each metal. metal observation P lots of bubbles produced Q few bubbles produced R no bubbles produced S very few bubbles produced What is the order of reactivity of these four metals, from most reactive to least reactive? A R→S→Q→P B P→S→Q→R C P→Q→S→R D Q→R→P→S

Question

The diagram shows iron nails which are left for one week in separate test-tubes with the conditions shown. rubber stopper oil iron nail iron nail iron nail water clean, dry air boiled water 1 2 3 Which test-tubes show evidence of rusting after one week? A 1 and 3 B 1 only C 2 and 3 D 2 only

Question

Pure metals can be combined to make alloys. Why are the alloys sometimes used rather than the metals they are made from? A Alloys are easier to extract and cheaper. B Alloys are easier to hammer into different shapes. C Alloys are harder and keep their shape better. D Alloys contain only atoms of the same size but pure metals do not.

Question

In the experiment shown, 100 cm3 of clean, dry air is passed backwards and forwards through a tube containing heated copper until there is no further decrease in the volume of the air. copper air gas syringe heat All of the gas is pushed into one syringe. What is the final reading on this gas syringe? A 0 cm3 B 21 cm3 C 79 cm3 D 100 cm3

Question

Sulfur dioxide, carbon monoxide and oxides of nitrogen are gaseous pollutants found in the air. Which pollutants contribute to acid rain? A carbon monoxide and sulfur dioxide B oxides of nitrogen and sulfur dioxide C oxides of nitrogen only D sulfur dioxide only

Question

The formulae for three organic compounds are listed. 1 C2H4 2 C4H8 3 C4H10 Which compounds belong to the same homologous series? A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Question

Which fuel could be gasoline? Is it obtained from petroleum? yes no Is it used as Is it used as fuel for cars? fuel for cars? yes no yes no A B C D

Question

Three hydrocarbons are separately mixed with aqueous bromine. Which row gives the correct observation for each hydrocarbon? H H H H H H C H H C C H C C H H H H H A colour changes from colour stays colour changes from orange to colourless unchanged orange to colourless B colour changes from colour changes from colour stays orange to colourless orange to colourless unchanged C colour stays colour stays colour changes from unchanged unchanged orange to colourless D colour stays colour changes from colour stays unchanged orange to colourless unchanged

Question

Which compound is formed when ethene reacts with steam? A ethane B ethanoic acid C ethanol D poly(ethene)

Question

Which statements about ethanoic acid are correct? 1 Its aqueous solution has a pH value of 10. 2 It reacts with metal carbonates to produce carbon dioxide gas. 3 It reacts with magnesium metal to produce hydrogen gas. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Question

Which statement explains why plastic bags made from poly(ethene) accumulate in oceans? A Poly(ethene) is a saturated molecule. B Poly(ethene) is made from hydrocarbon monomers. C Poly(ethene) reacts with water. D Poly(ethene) does not decompose in water.

Question

Which diagram shows the correct level of solvent at the start of a chromatography experiment? A B spot of sample spot of sample level of solvent level of solvent C D level of solvent spot of sample spot of sample level of solvent

Question

Which process is used to separate a mixture of liquids with different boiling points? A dissolving B crystallisation C filtration D fractional distillation

Question

Four different colourless solutions are each tested separately with aqueous sodium hydroxide and with acidified aqueous silver nitrate. Which row shows the results for sodium chloride? aqueous acidified aqueous sodium hydroxide silver nitrate A no visible reaction white precipitate B no visible reaction no visible reaction C white precipitate no visible reaction D white precipitate white precipitate 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.).