Chemistry 0620/21 May/June 2023: question paper and mark scheme

Question

The diagram shows the result of dropping a purple crystal into water. after water five hours purple solution purple crystal Which processes take place in this experiment? chemical diffusing dissolving reaction A B C D

Question

Which row about elements, mixtures and compounds is correct? metallic non-metallic mixture compound element element A copper methane brass sulfur B brass sulfur copper methane C copper sulfur brass methane D brass methane copper sulfur

Question

The atomic structures of four particles, W, X, Y and Z, are shown. electrons neutrons protons W 2 2 2 X 2 2 3 Y 2 3 2 Z 3 2 3 Which particles are isotopes of the same element? A W and X B W and Y C X and Y D X and Z

Question

Which statement explains why isotopes of the same element have the same chemical properties? A They have the same number of outer shell electrons. B They have the same number of neutrons. C They have different numbers of protons. D They have different mass numbers.

Question

Nitrogen forms a nitride ion with the formula N3–. Which particle does not have the same electronic configuration as the nitride ion? A Al 3+ B Cl – C Na+ D O2–

Question

Which row describes the formation of single covalent bonds in methane? A atoms share a pair of electrons both atoms gain a noble gas electronic structure B atoms share a pair of electrons both atoms have the same number of electrons in their outer shell C electrons are transferred from one both atoms gain a atom to another noble gas electronic structure D electrons are transferred from one both atoms have the same number atom to another of electrons in their outer shell

Question

Which formula is an empirical formula? A C2H4O B C4H8O2 C C3H7COOH D CH3CH2CH2COOH

Question

Heating iron sulfide, FeS2, in air produces sulfur dioxide. 4FeS2 + 11O2 → 2Fe2O3 + 8SO2 What is the maximum mass of sulfur dioxide produced from 120 kg of iron sulfide? A 64 kg B 128 kg C 240 kg D 512 kg

Question

Which substance produces hydrogen and bromine when electrolysed? A concentrated aqueous copper(II) bromide B concentrated aqueous sodium bromide C dilute aqueous potassium bromide D molten lead(II) bromide

Question

Which statements about hydrogen fuel cells are correct? 1 Water is formed as the only waste product. 2 Both water and carbon dioxide are formed as waste products. 3 The overall reaction is 2H2 + O2 → 2H2O. 4 The overall reaction is endothermic. A 1 and 3 B 1 and 4 C 2 and 3 D 2 and 4

Question

Ethene gas, C2H4, is completely burned in excess oxygen to form carbon dioxide and water. The equation for this exothermic reaction is shown. C2H4 + 3O2 → 2CO2 + 2H2O The table shows the bond energies involved in the reaction. bond energy bond in kJ / mol C=C 614 C–H 413 O=O 495 C=O 799 O–H 467 What is the total energy change in this reaction? A –954 kJ / mol B –1010 kJ / mol C –1313 kJ / mol D –1369 kJ / mol

Question

Which row describes the effect on the activation energy and the frequency of particle collisions when the temperature of a chemical reaction is increased? activation frequency energy of collisions A increases increases B no change increases C increases no change D no change no change

Question

Solid copper(II) sulfate exists in two different forms, anhydrous and hydrated. One of these forms is blue and the other is white. The change between these two forms is reversible. blue form white form What is the blue form and how is the change from the blue form to the white form brought about? change to blue form white form A anhydrous add water B anhydrous heat C hydrated add water D hydrated heat

Question

Sodium ions, Na+, and oxygen ions, O2–, combine with chromium ions to form a salt. The salt sodium dichromate has the formula Na2Cr2O7. What is the oxidation state of chromium in this salt? A +2 B +3 C +6 D +12

Question

The concentration of hydrogen ions in 100 cm3 of 0.1 mol / dm3 hydrochloric acid is higher than the concentration of hydrogen ions in 100 cm3 of 0.1 mol / dm3 ethanoic acid. Which statement explains the difference in hydrogen ion concentration? A Ethanoic acid is an organic acid. B Ethanoic acid has a lower pH than hydrochloric acid. C Ethanoic acid is partially dissociated. D Ethanoic acid is a strong acid.

Question

Which oxide is classified as an amphoteric oxide? A aluminium oxide B calcium oxide C copper(II) oxide D nitrogen oxide

Question

Which method produces the salt copper(II) carbonate? A Add copper(II) oxide to water, then add excess aqueous sodium carbonate. Filter off the precipitate. B Add copper(II) oxide to dilute sulfuric acid, then add excess aqueous sodium carbonate. Filter off the precipitate. C Add copper to dilute hydrochloric acid, then add aqueous sodium carbonate. Filter off the precipitate. D Add copper(II) oxide to excess aqueous sodium carbonate. Filter off the precipitate.

Question

Which statements about the trends across a period of the Periodic Table are correct? 1 Aluminium is more metallic than sodium. 2 Beryllium is more metallic than carbon. 3 Boron is more metallic than lithium. 4 Magnesium is more metallic than silicon. A 1 and 2 B 1 and 3 C 2 and 4 D 3 and 4

Question

Some information about elements in Group II of the Periodic Table is shown. time taken to make 10 cm3 density in melting element of hydrogen gas when 1 g of g / cm3 point / °C metal is added to cold water beryllium no reaction 1.85 1280 magnesium >300 seconds 1.74 650 calcium 60 seconds 1.54 850 strontium 30 seconds 2.62 768 barium 10 seconds 3.51 714 Which row shows the correct trends in reactivity, density and melting point of the elements going down Group II of the Periodic Table? reactivity density melting point A decreases down group increases down group decreases down group B decreases down group decreases down group no clear trend C increases down group no clear trend increases down group D increases down group no clear trend no clear trend

Question

A new element oxfordium, Ox, was discovered with the following properties. electrical formula bonding in a solubility conduction of element molecule of Ox2 insoluble in water does not conduct Ox2 Ox Ox In which group of the Periodic Table should the new element be placed? A Group III B Group V C Group VII D Group VIII

Question

Which row describes a similarity and a difference between chlorine and bromine? similarity difference A both are gases at room chlorine and bromine temperature and pressure have different colours B both exist as chlorine is more diatomic molecules dense than bromine C both have atoms with only bromine will react with seven outer-shell electrons aqueous sodium chloride D both react with aqueous chlorine is more reactive potassium iodide than bromine

Question

Which statement describes transition elements? A They have high densities and high melting points. B They have high densities and low melting points. C They have low densities and high melting points. D They have low densities and low melting points.

Question

Which gas is made when powdered zinc is added to dilute hydrochloric acid? A carbon dioxide B chlorine C hydrogen D oxygen

Question

The diagram represents the structure of a solid. Which solids does the diagram represent? brass graphite sodium chloride A B C D

Question

Steel is an alloy of iron. Which statement explains why steel is stronger than iron? A Steel contains carbon which is a very hard substance. B The carbon atoms in steel bond together very strongly. C The carbon atoms in steel make the iron atoms bond together very strongly. D The carbon atoms prevent layers of iron atoms from sliding over each other.

Question

Three students, X, Y and Z, are told that solid P reacts with dilute acids and also conducts electricity. The table shows the students’ suggestions about the identity of P. X Y Z copper iron graphite Which students are correct? A X, Y and Z B X only C Y only D Z only

Question

Which statement explains why aluminium appears to be unreactive? A It is coated in an oxide layer. B It has a low density. C It is low in the reactivity series. D It is solid at room temperature.

Question

During the electrolysis of aluminium oxide, the mass of the carbon anode changes. Which row describes the change and gives a reason for this change? mass change reason of the anode A decreases carbon reacts to form carbon dioxide B decreases carbon dissolves in molten cryolite C increases electrodes become coated with cryolite D increases electrodes become coated with aluminium

Question

Several processes are used to treat domestic water. Which row identifies a reason for the given process? process reason A chlorination removes impurities B filtration removes insoluble solids C sedimentation removes soluble solids D use of carbon kills bacteria

Question

What is the equation for photosynthesis? A CO2 + 3H2 → CH3OH + H2O B 6CO2 + 6H2O → C6H12O6 + 6O2 C C6H12O6 → 2C2H5OH + 2CO2 D C6H12O6 + 6O2 → 6CO2 + 6H2O

Question

Which statement describes how the C–H bonds in methane gas in the atmosphere contribute to global warming? A They absorb thermal energy from the Sun and emit some of this energy into space. B They absorb thermal energy from the Sun and emit all of this energy towards the Earth. C They absorb thermal energy from the Earth and emit all of this energy towards the Earth. D They absorb thermal energy from the Earth and emit some of this energy towards the Earth.

Question

The structural formulae of two hydrocarbons are shown. CH3CH2CH2CH3 CH3CH(CH3)CH3 Which statement about the hydrocarbons is correct? A They are both alkenes. B They decolourise aqueous bromine. C They are structural isomers. D They undergo addition reactions.

Question

The structural formula of compound Q is given. CH3CH2CH2COOCH2CH2CH3 What is compound Q? A butyl butanoate B butyl propanoate C propyl butanoate D propyl propanoate

Question

The fractional distillation of petroleum is shown. Which fraction contains hydrocarbons with the longest chain length? fuel gas A B C D petroleum bitumen

Question

Which equation represents the cracking of an alkane? A 3C2H4 → C6H12 B C6H12 + H2 → C6H14 C C6H14 → 6C + 7H2 D C6H14 → C2H4 + C4H10

Question

What is the structure of the product of the reaction of propene with bromine? A B C D H H H H Br H H Br H H H H H C C C Br H C C C H C C C Br Br C C C Br H H H H Br H H H H H H

Question

In reaction R, 2000 molecules of CH2=CH2 react to form a single molecule X only. 2000 CH2=CH2 → X Which terms describe reaction R, CH2=CH2 and X? reaction R CH2=CH2 X A addition monomer polymer B addition polymer monomer C substitution monomer polymer D substitution polymer monomer

Question

Part of the structure of a polymer is shown. H O H O N C N C N C H O Which statements about the polymer are correct? 1 The polymer is nylon. 2 The polymer is formed by condensation polymerisation. 3 There are ester linkages between the monomers. A 1 and 2 B 2 and 3 C 2 only D 3 only

Question

The concentration of acids and alkalis can be determined by titration. Which pieces of equipment are needed to perform a titration? 1 2 3 4 A 1 and 2 B 1 and 3 C 2 and 3 D 2 and 4

Question

Which chromatogram shows how the Rf value of a substance is calculated? A B C D x y x x x y y y y y x x Rf = x Rf = x Rf = y Rf = y 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.).