0620_w20_qp_33
A paper of Chemistry, 0620
Questions:
8
Year:
2020
Paper:
3
Variant:
3
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1
The diagram shows part of the Periodic Table. I II III IV V VI VII VIII Ca H Pt Al Cl Br Ar I N O F K Answer the following questions using only the symbol of the elements in the diagram. Each symbol may be used once, more than once or not at all. State the symbol of the element that: is a fuel which is a gas at room temperature is used to kill bacteria in water forms a stable ion of type X3+ is a grey‑black non-metallic solid at room temperature forms an ion which, on addition of aqueous sodiumhydroxide, gives a white precipitate which is soluble in excess aqueous sodium hydroxide. Sulfur has several isotopes. Identify one correct statement about isotopes. Tick one box. They are molecules with the same number of neutrons but different numbers of protons. They are atoms with the same number of protons but different numbers of neutrons. They are molecules with the same number of protons but different numbers of electrons. They are atoms with the same number of neutrons but different numbers of protons.  An isotope of sulfur is shown. 33S Deduce the number of protons and neutrons in this isotope. number of protons number of neutrons  Complete the electronic structure of a sulfur atom. S  
2. Atoms, elements and compounds  →  2.2. Atomic structure and the Periodic Table
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2
The table shows the mass of air pollutants, in nanograms, in 1000 cm3 samples of air taken over a four month period. mass of pollutant in 1000 cm3 of air / nanograms month oxides of nitrogen sulfur dioxide carbon monoxide ozone particulates August 106.0 3.0 2.1 29.5 18.5 September 147.5 5.5 2.4 21.1 35.5 October 179.3 3.5 2.0 20.3 22.5 November 214.0 3.6 2.6 12.8 29.4 Answer these questions using only the information in the table. Name the pollutant that shows a decrease in concentration between August and November. Calculate the mass of oxides of nitrogen in 250 cm3 of the sample of air taken in August.  nanograms Carbon monoxide is produced by the incomplete combustion of fossil fuels. State the meaning of the term incomplete combustion. Give one adverse effect of carbon monoxide on health. Carbonmonoxide is also produced when methane reacts with steam in the presence of a catalyst. Explain why a catalyst is used in this reaction. Methane is an air pollutant. State one source of methane in the air. Complete the chemical equation for the reaction of carbon monoxide with oxygen. CO + O2 → CO2 Complete the energy level diagram for the reaction of carbonmonoxide with oxygen by writing these words on the diagram: ● ● reactants ● ● products. energy progress of reaction  Explain, using information on the energy level diagram, how you know that this reaction is exothermic. Describe a test for carbondioxide. test result  Identify which one of these pH values represents the pH of a solution of carbondioxide in water. Draw a circle around the correct answer. pH 6 pH 7 pH 8 pH 14 
10. Chemistry of the environment  →  10.3. Air quality and climate
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Some properties of four substances, A, B, C and D, are shown in the table. substance electrical conductivity when solid electrical conductivity when molten melting point solubility in water A does not conduct does not conduct low insoluble B conducts conducts high insoluble C does not conduct does not conduct very high soluble D does not conduct conducts high soluble Answer these questions using only the information in the table. State which substance, A, B, C or D, is sulfur. Explain your answer. substance explanation  State which substance, A, B, C or D, is sodiumchloride. Explain your answer. substance explanation  
2. Atoms, elements and compounds  →  2.5. Simple molecules and covalent bonds
2. Atoms, elements and compounds  →  2.4. Ions and ionic bonds
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4
The structure of crotonicacid is shown. C H C C H H O O H H C H On the structure, draw a circle around the functional group which shows that this is an unsaturated compound. Deduce the formula of crotonicacid to show the number of carbon, hydrogen and oxygen atoms. Complete the table to calculate the relative molecular mass of crotonicacid. Use your Periodic Table to help you. type of atom number of atoms relative atomic mass carbon 4 × 12 = 48 hydrogen oxygen  relative molecular mass = Acids react with bases such as calciumoxide. Complete the word equation for the reaction of nitricacid with calciumoxide. nitric acid + calcium oxide +  Calciumoxide is manufactured from limestone by thermal decomposition. Give the name of the main chemical compound in limestone. State the meaning of the term thermal decomposition. Calciumoxide reacts with water to produce slaked lime. State one use of slaked lime. 
11. Organic chemistry  →  11.7. Carboxylic acids
9. Metals  →  9.4. Reactivity series
12. Experimental techniques and chemical analysis  →  12.5. Identification of ions and gases
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The formula of ethanol is C2H6O. Draw the structure of ethanol to show all of the atoms and all of the bonds.  Ethanol is a liquid at room temperature. Describe the motion and separation of the particles in ethanol. motion separation  Name the two products formed when ethanol undergoes complete combustion.  Ethanol can be manufactured by the fermentation of glucose. One condition is using enzymes in yeast. State two other conditions for fermentation.  Name the method used to separate the ethanol from the reaction mixture after fermentation is complete. Alcohols can also be manufactured from alkenes. Complete the word equation for the manufacture of ethanol by this method. + ethanol  
11. Organic chemistry  →  11.6. Alcohols
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6
The electrolysis of concentrated hydrochloricacid produces gases at each electrode. Describe the electrolysis of concentrated hydrochloricacid. In your answer include: ● ● a labelled diagram of the apparatus used for the electrolysis and collection of gases ● ● the names of the products formed at the positive and the negative electrode. positive electrode negative electrode  Carbondioxide is produced when hydrochloricacid reacts with sodiumcarbonate. Complete the chemical equation for this reaction. Na2CO3 + 2HCl → NaCl + + CO2 Carbondioxide reacts with carbon to produce carbonmonoxide. CO2 + C → 2CO Explain how this equation shows that carbondioxide has been reduced. 
4. Electrochemistry  →  4.1. Electrolysis
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7
A student investigated the rate of reaction of excess calciumcarbonate with dilutehydrochloricacid in a conical flask by two different methods. Method 1: Measure the volume of carbondioxide produced at 10second intervals. Method 2: Measure the loss in mass of the reaction mixture by weighing at 10second intervals. Suggest one advantage of Method1 compared with Method2. Explain why there is a decrease in mass of the reaction mixture in Method2. The graph shows how the volume of carbondioxide changes as the reaction proceeds, using Method1. time / s volume of carbon dioxide / cm3 The student used large pieces of calciumcarbonate. Answer these questions using information from the graph. Describe how the rate of this reaction changes with time. Deduce the time taken to collect 36 cm3 of carbondioxide.  time = s The experiment is repeated using smaller pieces of calciumcarbonate. Draw a line on the grid to show how the volume of carbondioxide changes with time when smaller pieces of calciumcarbonate are used. All other conditions stay the same. Describe what effect the following changes have on the rate of this reaction. ● ● The temperature is increased. All other conditions stay the same. ● ● The concentration of the hydrochloric acid is decreased. All other conditions stay the same.  
6. Chemical reactions  →  6.2. Rate of reaction
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8
This question is about metals and compounds of metals. Sodium is a metal in GroupI of the Periodic Table. Identify two correct statements about sodium. Tick two boxes. It is a relatively soft metal. It has a high melting point. It forms coloured chlorides. It has a lower density than most metals. It is a good insulator.  Some changes of state of sodium are shown. solid sodium melting R liquid sodium sodium gas S condensing Give the names of the changes of state represented by R and S. R S  The table compares the reactions of four metals with dilute and with concentrated hydrochloricacid. metal observation with dilute hydrochloric acid observation with concentrated hydrochloric acid beryllium bubbles form rapidly bubbles form very rapidly copper no bubbles seen no bubbles seen iron bubbles form very slowly bubbles form slowly nickel no bubbles seen bubbles form slowly Put the four metals in order of their reactivity. Put the least reactive metal first. least reactive most reactive  Crystals of magnesium chloride, MgCl 2•6H2O, can be prepared by adding excess magnesium powder to dilute hydrochloricacid. Describe how to prepare a sample of pure dry magnesiumchloride crystals after the reaction is complete. In your answer describe how to: ● ● remove the excess magnesium from the reaction mixture ● ● crystallise the magnesiumchloride ● ● dry the crystals. When magnesium reacts with concentrated sulfuricacid, sulfurdioxide is produced. Complete this description of the test for sulfurdioxide using words from the list. blue chloride colourless green manganate(sulfate(The test for sulfurdioxide uses acidified aqueous potassium . The colour change is from purple to .  Green nickel(sulfate crystals turn yellow when heated. NiSO4•7H2O NiSO4 + 7H2O green yellow nickel(sulfate nickel(sulfate Suggest how you would change yellow nickel(sulfate to green nickel(sulfate. Identify which word best describes green nickel(sulfate with the formula NiSO4•7H2O. Draw a circle around the correct answer. anhydrous decomposed hydrated oxidised reduced 
9. Metals  →  9.4. Reactivity series
8. The Periodic Table  →  8.2. Group I properties
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