0620_w18_qp_33
A paper of Chemistry, 0620
Questions:
8
Year:
2018
Paper:
3
Variant:
3
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1
The electronic structures of five atoms, A, B, C, D and E, are shown. A B C D E Answer the following questions about these structures. Each structure may be used once, more than once or not at all. State which structure, A, B, C, D or E, represents: an atom with a total of eight electrons an atom in GroupV of the Periodic Table an atom with a complete outer shell of electrons an atom of a metallic element an atom which forms a stable ion with a single positive charge. Complete the table to show the number of electrons, neutrons and protons in the neon atom and copper ion shown. number of electrons number of neutrons number of protons 22Ne 65Cu+  
2. Atoms, elements and compounds  →  2.2. Atomic structure and the Periodic Table
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The table shows the concentrations of the ions present in the solution obtained from squid nerve cells and in human blood plasma. ion present solution obtained from squid nerve cells human blood plasma concentration in g / 1000 cm3 concentration in g / 1000 cm3 sodium 1.15 3.25 potassium 15.60 0.16 magnesium 0.03 0.04 chloride 3.55 3.65 hydrogencarbonate trace 1.50 Answer these questions using only information from the table. Give two major differences between the concentrations of the ions present in the solution obtained from squid nerve cells and in human blood plasma.  Calculate the mass of potassium ions present in 250 cm3 of the solution obtained from squid nerve cells.  mass of potassium ions = g Describe a test for sodium ions. test result  Squid produce an ink which contains a compound called taurine. The structure of taurine is shown. S O O C H H C N H H H H O H Deduce the molecular formula of taurine showing the number of carbon, hydrogen, oxygen, nitrogen and sulfur atoms. The ink used for writing is a mixture of dyes. These dyes can be separated by paper chromatography. Describe how to separate a mixture of dyes using paper chromatography. Include a labelled diagram in your answer.  
12. Experimental techniques and chemical analysis  →  12.5. Identification of ions and gases
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Brass is an alloy of copper and zinc. Which one of the following diagrams best represents an alloy? J K L M Brass is used to make the propellers of ships rather than pure copper or pure zinc. Suggest a property of brass which explains this. The chemical equation for the reaction of zinc with concentrated nitricacid is shown. Zn + 4HNO3 Zn(NO3)2 + 2NO2 + 2H2O Complete the word equation for this reaction. zinc + nitric acid + +  One of the compounds in this equation is a pollutant gas which contributes to acid rain. Identify the pollutant gas and state a common source of it. pollutant gas source  Zinc oxide is reduced by heating it with carbon. ZnO + C Zn + CO How does this equation show that zincoxide is reduced? When green iron(sulfate is heated it loses its water of crystallisation. The reaction is reversible. Complete the following equation by writing the sign for a reversible reaction in the box. FeSO4.7H2O FeSO4 + 7H2O green white  Use the information in the equation to suggest how to change white iron(sulfate into green iron(sulfate. 
9. Metals  →  9.4. Reactivity series
9. Metals  →  9.3. Alloys and their properties
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The structure of compound P is shown. C C H H H H C COOH H H C H compound P What feature of the structure of compoundP shows that it is unsaturated? Describe the colour change when an excess of compoundP is added to aqueous bromine. from to  CompoundP has a –COOH functional group. Draw the structure of the –COOH functional group. Show all of the atoms and all of the bonds.  What effect would compoundP have on litmus solution? The concentration of aqueous sodiumhydroxide can be found by reacting it with an acid of known concentration. The graph shows how the pH of aqueous sodium hydroxide in a conical flask changes as acid is added to it. volume of acid added / cm3 pH Describe how the pH changes as the acid is added. What is the pH of the aqueous sodiumhydroxide before the acid is added? What volume of acid has been added when the solution reaches neutral pH? 
7. Acids, bases and salts  →  7.1. The characteristic properties of acids and bases
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When sulfur vapour falls on to a cold surface, small crystals of solid sulfur form. Use the kinetic particle model to describe the arrangement and motion of the particles in sulfur when it is: ● ● a gas ● ● a solid  Sulfurdioxide is formed when copper reacts with hot concentrated sulfuricacid. Balance the chemical equation for this reaction. Cu + H2SO4 CuSO4 + SO2 + H2O  Hot copper reacts with chlorine to form copper(chloride. Describe a test for chloride ions. test result  Molten copper(chloride can be electrolysed using the apparatus shown. + – power supply On the diagram label: ● the cathode ● the electrolyte  Predict the products of this electrolysis at: the positive electrode the negative electrode.  Give one observation that is made at the positive electrode. 
4. Electrochemistry  →  4.1. Electrolysis
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The diagrams show the structures of four substances, R, S, T and U. R S T U K+ I– K+ I– I– K+ K+ I– K+ I– K+ I– I– K+ K+ I– Mn Mn Mn Mn Mn Mn Mn Mn Mn Mn Mn Mn N N N N N N N N N N C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C State which one of these substances, R, S, T or U: is a compound conducts electricity when solid has the lowest melting point is a macromolecule can act as a catalyst. SubstanceS is potassiumiodide. When aqueous potassiumiodide reacts with aqueous chlorine, the solution turns brown. Name the brown substance that forms. Using ideas about the reactivity of the halogens, suggest why the brown substance forms. Potassium salts are present in many fertilisers. Which one of the following compounds is also present in many fertilisers? Tick one box. lead(bromide calcium phosphate copper(sulfide tin(oxide  Many fertilisers contain ammonium salts. Explain why farmers do not add calcium hydroxide (slaked lime) to the soil at the same time as fertilisers containing ammonium salts. 
10. Chemistry of the environment  →  10.2. Fertilisers
9. Metals  →  9.4. Reactivity series
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A student investigates the rate of reaction of iron powder with dilute hydrochloricacid. dilute hydrochloric acid iron powder Complete the diagram to show the apparatus the student could use to collect and measure the gas produced. Label your diagram. The graph shows the results the student obtained using dilute hydrochloricacid of concentration 0.2 mol / dm3 and an excess of iron powder. time / minute volume of gas / cm3 Use the graph to deduce: the time that the reaction was complete the volume of gas produced when the reaction was complete. The student repeated the experiment using a lower concentration of dilute hydrochloricacid. All other conditions were kept the same. On the grid, draw a graph to show how the volume of gas changes with time when a lower concentration of dilute hydrochloricacid is used. Iron is extracted from iron ore using a blast furnace. The solid substances added to the blast furnace are iron ore, coke and limestone (calciumcarbonate). State the name of an ore of iron. Complete the sentences about the reactions which occur in a blast furnace using words from the list. air decomposes dioxide monoxide nitrogen oxidises slag tetrachloride The coke burns in a blast of hot to form carbondioxide. This reacts with further hot coke to form carbon . This gas reduces the iron(oxide in the iron ore to iron. The limestone to form lime (calciumoxide) which reacts with impurities in the iron to form .  
9. Metals  →  9.6. Extraction of metals
6. Chemical reactions  →  6.2. Rate of reaction
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The table shows the properties of some GroupVII elements. element boiling point in °C density at room temperature in g / cm3 physical state at room temperature fluorine –188 0.0017 chlorine 0.0032 gas bromine 3.1 liquid iodine 4.9 solid Use this information to: ● identify the physical state of fluorine at room temperature ● estimate the boiling point of chlorine.  Suggest why the density of chlorine is much lower than the densities of bromine and iodine. Chlorine is used in water treatment. Why is chlorine added to water? State one major use of water in industry. Chlorine reacts with phosphorus to form phosphorus(chloride. Balance the chemical equation for this reaction. P + Cl 2 2PCl 3  Complete the dot-and-cross diagram to show the electron arrangement in a molecule of chlorine. Show outer shell electrons only. Cl Cl  
8. The Periodic Table  →  8.3. Group VII properties
10. Chemistry of the environment  →  10.1. Water
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