0620_w21_qp_31
A paper of Chemistry, 0620
Questions:
8
Year:
2021
Paper:
3
Variant:
1
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1
A list of formulae is shown. Al Cl 3 CaCO3 CO CO2 CoCl 2 CuSO4 MgCl 2 N2 NaCl NH3 O2 SO2 Answer the following questions using these formulae. Each formula may be used once, more than once or not at all. State which formula represents: a compound that changes colour from white to blue when water is added a compound that is used to make cement an element that forms 78% of clean, dry air a compound that contains an ion with a single positive charge a compound that dissolves in water to form an alkaline solution. Complete the dot-and-cross diagram to show the electron arrangement in a molecule of ammonia. N H H H  State whether magnesiumoxide is a basic oxide or an acidic oxide. Give a reason for your answer. 
3. Stoichiometry  →  3.1. Formulae
6. Chemical reactions  →  6.4. Redox
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2
The table shows the masses of some of the ions in 1000 cm3 of rainwater. name of ion formula of ion mass of ion in 1000 cm3 of rainwater / mg NH4 + 0.08 calcium Ca2+ 0.13 chloride Cl – 1.30 magnesium Mg2+ 0.08 nitrate NO3 – 0.70 potassium K+ 0.08 sodium Na+ 0.80 SO4 2– 1.60 Answer these questions using only the information in the table. State which of the positive ions has the highest concentration. Name the compound containing NH4 + and SO4 2– ions. Calculate the mass of magnesium ions in 400 cm3 of rainwater.  mass = mg Describe a test for chloride ions. test observations  Small amounts of carboxylicacids are also present in rainwater. The structure of tartaric acid is shown. C H H O C C O O O H C H H O O H On the structure draw a circle around one alcohol functional group. Deduce the formula of tartaricacid to show the number of carbon, hydrogen and oxygen atoms. Tartaricacid can be converted into compoundA. The formula of compoundA is C3H4O3. Complete the table to calculate the relative molecular mass of compoundA. type of atom number of atoms relative atomic mass carbon 3 × 12 = 36 hydrogen oxygen  relative molecular mass =  
12. Experimental techniques and chemical analysis  →  12.5. Identification of ions and gases
3. Stoichiometry  →  3.1. Formulae
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3
The diagram shows a blast furnace used in the extraction of iron. mixture of iron ore, coke and limestone molten slag molten iron E B C D Air is blown into the furnace. State which letter on the diagram, B, C, D or E, shows where air is blown into the furnace. Complete the chemical equation for the reduction of iron(oxide in the blast furnace. Fe2O3 + 3C → Fe + CO Explain how this equation shows that iron(oxide is reduced. Calciumcarbonate is added to the blast furnace. The calciumcarbonate undergoes thermal decomposition. Complete the word equation for this reaction. calcium carbonate → +  One of the products of this reaction reacts with impurities in the iron to form slag. Use the information in the diagram to suggest how you know that molten slag is less dense than molten iron. Use words from the list to complete these sentences about how steel is made from iron. acidic basic chlorides methane neutral nitrogen oxides oxygen sulfates A gas is blown through the molten iron. The name of this gas is . Acidic gases are formed. These acidic gases react with .  State one use of mild steel. Metals such as chromium are added to iron to make stainless steel. The symbol for an isotope of chromium is shown. 53Cr Deduce the number of electrons, neutrons and protons in one atom of this isotope of chromium. number of electrons number of neutrons number of protons  Chromium conducts electricity and is shiny. Give two other physical properties of chromium that are characteristic of all metals.  
9. Metals  →  9.6. Extraction of metals
9. Metals  →  9.4. Reactivity series
12. Experimental techniques and chemical analysis  →  12.5. Identification of ions and gases
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The table shows some properties of the Group I elements. element melting point / °C density in g / cm3 observations during reaction with water lithium slow bubbling no flame sodium rapid bubbling no flame potassium 0.86 rapid bubbling lilac flame rubidium 1.53 caesium 1.88 explodes Complete the table by predicting: ● the melting point of rubidium ● the density of lithium. Predict the observations when rubidium reacts with water. Deduce the electronic structure of potassium. Use the Periodic Table to help you. Lithium reacts with water to produce aqueous lithiumhydroxide and a gas which ‘pops’ with a lighted splint. Name the gas which ‘pops’ with a lighted splint. Choose one pH value from the list that best describes the pH of aqueous lithiumhydroxide. Draw a circle around the correct answer. pH 2 pH 5 pH 7 pH 13 Lithium reacts with nitrogen. Complete the chemical equation for this reaction. Li + N2 → Li3N 
12. Experimental techniques and chemical analysis  →  12.5. Identification of ions and gases
8. The Periodic Table  →  8.2. Group I properties
9. Metals  →  9.4. Reactivity series
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5
The table shows the structures of some organic compounds. compound structure of compound homologous series G H C H H C H H C O O H carboxylic acid H H C H H C H H C H J H C H H H C H H Complete the table by naming the homologous series. The first one has been done for you. Draw the structure of a compound containing two carbon atoms which belongs to the same homologous series as compoundH. Show all of the atoms and all of the bonds.  State which compound in the table is an unsaturated hydrocarbon. Explain your answer. State which compound in the table reacts with aqueous sodiumhydroxide. Explain your answer. State the names of the two compounds formed during the complete combustion of compoundJ. and CompoundH can be polymerised. State the general name given to the small units which join together to form a polymer. Terylene is also a polymer. Give one use of Terylene. 
11. Organic chemistry  →  11.1. Formulae, functional groups and terminology
11. Organic chemistry  →  11.2. Naming organic compounds
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6
The diagram shows part of the structures of sodiumbromide and graphite at room temperature and pressure. Na+ Br – Na+ Br – Na+ Br – Na+ Br – Br – Na+ Na+ Br – Describe the physical properties of these substances in terms of: ● volatility sodium bromide graphite ● solubility in water sodium bromide graphite ● electrical conductivity when solid. sodium bromide graphite  When dilute sulfuricacid is electrolysed using inert electrodes, oxygen gas is produced at the positive electrode. Name the gas produced at the negative electrode. Aqueous sodiumbromide reacts with aqueous chlorine. Complete the word equation for this reaction. sodium bromide + chlorine → +  Explain in terms of the reactivity of the halogens why aqueous sodiumchloride does not react with aqueous bromine. 
4. Electrochemistry  →  4.1. Electrolysis
9. Metals  →  9.4. Reactivity series
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7
This question is about nitrogen and compounds of nitrogen. When nitrogen is cooled to below –196 °C it changes state from gas to liquid. Name the change of state from gas to liquid. Use the kinetic particle theory to describe the differences between nitrogen gas and liquid nitrogen in terms of: ● the separation of the particles ● the motion of the particles.  Oxides of nitrogen are pollutants in the air. State one source of oxides of nitrogen in the air. Oxides of nitrogen contribute to acid rain. Give one adverse effect of acid rain on buildings. Nitric acid contains the nitrate ion. Use words from the list to complete the sentences to describe the test for nitrate ions. aluminium ammonia chloride copper hydroxide iron oxygen sulfate Put the sample in a test‑tube then add aqueous sodium . Then add . Warm gently. A gas is produced. The name of this gas is .  Nitric acid reacts with calciumcarbonate. Complete the word equation for this reaction. nitric acid + calcium carbonate → + +  
12. Experimental techniques and chemical analysis  →  12.5. Identification of ions and gases
10. Chemistry of the environment  →  10.3. Air quality and climate
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The rate of decomposition of aqueous hydrogenperoxide, H2O2, is increased by an enzyme. 2H2O2 → 2H2O + O2 The rate of reaction is found by measuring the volume of oxygen gas given off as the reaction proceeds. The results are shown on the graph. time / s volume of oxygen gas / cm3 Deduce the volume of oxygen gas released when the reaction is complete.  volume = cm3 Deduce the volume of oxygen gas produced 50seconds from the start of the reaction.  volume = cm3 The experiment was repeated using hydrogenperoxide of a higher concentration. All other conditions stayed the same. Draw a line on the grid to show how the volume of oxygen changes with time when hydrogenperoxide of a higher concentration is used. Describe the effect each of the following has on the rate of decomposition of hydrogen peroxide. ● The reaction is carried out at a lower temperature. All other conditions stay the same. ● The reaction is carried out without an enzyme. All other conditions stay the same.  Some metal oxides catalyse the decomposition of hydrogenperoxide. The table shows the time taken to produce 20 cm3 of oxygen gas using three different metal oxide powders as catalysts. All other conditions stay the same. metal oxide time taken to produce 20 cm3 of oxygen gas / s iron(oxide lead(oxide manganese(oxide Put the three oxides in order of their ability to catalyse the reaction. Put the best catalyst first. best catalyst worst catalyst  The experiments with the metal oxide catalysts used powdered oxide. Describe the effect on the rate of decomposition of hydrogenperoxide when large pieces of catalyst are used instead of powdered catalyst. All other conditions stay the same. 
6. Chemical reactions  →  6.2. Rate of reaction
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