Chemistry 0620/21 October/November 2020: question paper and mark scheme

Question

Which gas has the slowest rate of diffusion? A H2 B NH3 C CH4 D CO2

Question

A mixture of colourless amino acids is separated using chromatography. The solvent used is propanol. The chromatogram is sprayed with a locating agent. Which row describes the purpose of the propanol and the locating agent? purpose of propanol purpose of locating agent A to make the individual to prevent the amino acids amino acids visible moving any further B to move the amino acids up to make the individual the chromatography paper amino acids visible C to move the amino acids up to prevent the amino acids the chromatography paper moving any further D to prevent the amino acids to make the individual moving too far up the paper amino acids visible

Question

Which piece of apparatus can only measure a single fixed volume? A 250 cm3 beaker B 50 cm3 burette C 100 cm3 measuring cylinder D 25 cm3 pipette

Question

In the chromatography experiment shown, which label represents the solvent front? A B D C

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The atomic structure of four particles are shown. electrons protons neutrons P 18 17 18 Q 18 17 20 R 17 17 18 S 17 17 20 Which particles have the same chemical properties? A P and R only B P and S C P, Q and R D R and S

Question

The arrangements of the electrons in two ions formed from elements X and Y are shown. X Y n = 20 n = 20 p = 19 p = 17 Which equation represents the reaction between elements X and Y? A X2 + 2Y → 2X+ + 2Y– B X2 + 2Y → 2X– + 2Y+ C 2X + Y2 → 2X+ + 2Y– D 2X + Y2 → 2X– + 2Y+

Question

Which diagram shows the outer shell electron arrangement in a molecule of methanol, CH3OH? A B H H H C O H H C O H H H C D H H H C O H H C O H H H

Question

Which statement about silicon dioxide, SiO2, is correct? A It conducts electricity because it contains free electrons. B It is a macromolecule with four oxygen atoms bonded to each silicon atom. C It is a simple covalent molecule. D Its structure is similar to graphite.

Question

Rubidium is in Group I of the Periodic Table and bromine is in Group VII. Rubidium reacts with bromine to form an ionic compound. Which row shows the electron change taking place for rubidium and the correct formula of the rubidium ion? electron change formula of ion formed A electron gained Rb+ B electron gained Rb– C electron lost Rb+ D electron lost Rb–

Question

Which statement explains why graphite is used as a lubricant? A All bonds between the atoms are weak. B It conducts electricity. C It has a low melting point. D Layers in the structure can slide over each other.

Question

Sodium carbonate reacts with sulfuric acid to form carbon dioxide, water and a sodium salt. An incomplete equation for the reaction is shown. Na2CO3 + H2SO4 → CO2 + H2O + …… What is the formula of the sodium salt? A Na2(SO4)2 B Na(SO4)2 C Na2SO4 D NaSO4

Question

The relative atomic mass of chlorine is 35.5. When calculating relative atomic mass, which particle is the mass of a chlorine atom compared to? A a neutron B a proton C an atom of carbon-12 D an atom of hydrogen-1

Question

What is the empirical formula of an oxide of iron, formed by reacting 2.24 g of iron with 0.96 g of oxygen? A FeO B Fe2O C Fe2O3 D Fe3O4

Question

Which reaction takes place at the cathode during the electrolysis of molten nickel(II) chloride? A Cl 2 + 2e– → 2Cl – B 2Cl – → Cl 2 + 2e– C Ni → Ni2+ + 2e– D Ni2+ + 2e– → Ni

Question

Sodium nitrate is added to water in a beaker and stirred until it dissolves. At the end of the experiment, the beaker feels cold. Which row describes the reaction? temperature type of of solution reaction A decreases endothermic B decreases exothermic C increases endothermic D increases exothermic

Question

Which substance does not require oxygen in order to produce energy? A coal B hydrogen C natural gas 235 D U

Question

Ethene reacts with hydrogen to form ethane. H H H H C C + H H → H C C H H H H H The bond energies are shown in the table. bond energy bond in kJ / mol C–C +350 C–H +410 H–H +436 C=C +614 What is the energy change for the reaction? A –290 kJ / mol B –120 kJ / mol C +120 kJ / mol D +290 kJ / mol

Question

A sign displayed in a flour mill is shown. DANGER Explosion Hazard No Smoking No Open Flames Which statement explains why there is a danger of explosion in a flour mill? A Flour burns very quickly because it is a fine powder. B Flour is a catalyst for combustion. C Flour mills get hot and speed up the rate of combustion. D The combustion of flour is exothermic.

Question

A student investigates the effect of concentration on the rate of reaction between calcium carbonate and hydrochloric acid. He follows the method shown. ● Place 1 g of calcium carbonate in a conical flask. ● Add excess hydrochloric acid. ● Let the reaction continue until no more gas is made. ● Repeat the experiment with different concentrations of hydrochloric acid. Which essential step has been left out of the method if he is to work out the rate of the reaction? A heating the reaction mixture B placing a bung in the flask C timing the reaction D using a catalyst

Question

The reaction between sulfur dioxide and oxygen is shown. 2SO2(g) + O2(g) 2SO3(g) The reaction is exothermic. Which of the changes shifts the position of equilibrium to the right? 1 Increase the concentration of oxygen. 2 Increase the pressure. 3 Increase the temperature. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 only

Question

The reaction between chlorine and bromide ions is a redox reaction. Cl 2 + 2Br – → 2Cl – + Br2 What is the change in oxidation state of the reducing agent in this reaction? A –2 to 0 B –1 to 0 C 0 to –1 D 0 to +1

Question

What is a characteristic of acids? A Acids turn methyl orange indicator yellow. B Acids have a high pH value. C Acids react with ammonium salts to give ammonia gas. D Acids react with carbonates to produce salts.

Question

Zinc oxide is an amphoteric oxide. Which row describes the reactions of zinc oxide? reaction reaction with alkalis with acids A B C D

Question

A student carries out an experiment to prepare pure magnesium sulfate crystals. The diagram shows the first stage of the preparation. stirrer magnesium carbonate dilute sulfuric acid He adds magnesium carbonate until no more reacts. Which process should he use for the next stage? A crystallisation B evaporation C filtration D neutralisation

Question

Elements P and Q have the same number of electron shells. Q has more electrons in its outer shell than P. Which statements are correct? 1 P and Q are in the same group of the Periodic Table. 2 P and Q are in the same period of the Periodic Table. 3 P has a greater tendency to form positive ions than Q. 4 The oxides of Q are more basic than those of P. A 1 and 3 B 1 and 4 C 2 and 3 D 2 and 4

Question

The positions of four elements in the Periodic Table are shown. Which element is a gas that displaces iodine from sodium iodide? B C D A

Question

A flammable gas needs to be removed from a tank at an industrial plant. For safety reasons, an inert gas is used. Which gas is suitable? A argon B hydrogen C methane D oxygen

Question

A strip of aluminium is placed into a test-tube containing aqueous lead(II) nitrate and left for several minutes. Aluminium is higher than lead in the reactivity series. strip of aluminium no change Pb(NO3)2 solution Which statement explains why lead is not displaced by this strip of aluminium? A A thin insoluble layer of aluminium nitrate forms on the aluminium. B Nitrate ions are reduced in aqueous solution. C The ionic bonds between lead and nitrate ions are too strong. D There is an unreactive oxide layer on the aluminium.

Question

Which statements about the metal zinc are correct? 1 It is extracted from the ore bauxite. 2 It is used to galvanise steel. 3 It is used to make the alloy brass. 4 It reacts with dilute hydrochloric acid to produce hydrogen gas. A 2 and 3 only B 1, 2 and 4 C 1, 3 and 4 D 2, 3 and 4

Question

What is the symbol of the metal used in the manufacture of aircraft because of its strength and low density? A Al B Cu C Fe D Zn

Question

Ammonia is manufactured using the Haber process. Which statement about this process is correct? A The catalyst used for this reaction is vanadium pentoxide. B The hydrogen used is extracted from air. C Using a high pressure increases the yield of ammonia. D Using a high temperature increases the yield of ammonia.

Question

Iron can be protected from rusting by attaching a piece of a more reactive metal, e.g. magnesium, to the iron. Which equation represents the reaction that takes place? A Fe(s) → Fe2+(aq) + 2e– B Fe2+(aq) + 2e– → Fe(s) C Mg(s) → Mg2+(aq) + 2e– D Mg2+(aq) + 2e– → Mg(s)

Question

Which row describes two uses of sulfur dioxide? use 1 use 2 A bleaching paper pulp neutralising acidic industrial waste B bleaching paper pulp preserving food and drink C extracting iron from hematite neutralising acidic industrial waste D extracting iron from hematite preserving food and drink

Question

Part of the carbon cycle is shown. combustion Q R glucose CO2 plant CH4 P What are processes P, Q and R? P Q R A decomposition respiration photosynthesis B respiration photosynthesis decomposition C respiration decomposition photosynthesis D photosynthesis respiration decomposition

Question

The structures of four organic molecules are shown. 1 2 H H H H H H H H C C C H H C C C C H H H H H H H C H H C H H C H H H 3 4 H H H H H C C C H H C H H H H H C H H C H H C C C H H H H H H C H H Which molecules are structural isomers of structure 1? A 2 and 4 B 2 only C 3 and 4 D 3 only

Question

Which chemical equation for the substitution of an alkane with chlorine is correct? A C3H8 + Cl 2 → C3H7Cl + HCl B C3H6 + Cl 2 → C3H6Cl 2 C C3H8 + Cl 2 → C3H6Cl 2 + H2 D C3H6 + Cl 2 → C3H5Cl + HCl

Question

Propene is an alkene that reacts with bromine, steam and hydrogen as shown. H H C C C H H H H bromine steam hydrogen J K L What are the products of these reactions? J K L A bromopropane propanol butane B dibromopropane propanoic acid propane C dibromopropane propanol propane D bromopropane propanoic acid butane

Question

The flow chart shows the preparation of ethanol and some important chemistry of ethanol. fermentation process Y substance X ethanol carbon dioxide + substance Z What are X, Y and Z? X Y Z A yeast combustion oxygen B glucose combustion steam C glucose polymerisation water D yeast fermentation glucose

Question

Which statements about aqueous ethanoic acid are correct? 1 It is an alkane. 2 It reacts with sodium carbonate to form carbon dioxide. 3 It changes the colour of litmus solution from blue to red. 4 It is a hydrocarbon. A 1 and 2 B 1 and 4 C 2 and 3 D 3 and 4

Question

The structure of a polymer is shown. H H C C H CH3 n Which monomer forms this polymer? A ethane B ethene C propane D propene 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 85 88 89 91 93 96 – 101 103 106 108 112 115 119 122 128 127 131 16 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 89–103 104 105 106 107 108 109 110 111 112 114 116 actinoids Fr Ra Rf Db Sg Bh Hs Mt Ds Rg Cn Fl Lv francium radium rutherfordium dubnium seaborgium bohrium hassium meitnerium darmstadtium roentgenium copernicium flerovium livermorium – – – – – – – – – – – – – 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.).