0620_w16_qp_31
A paper of Chemistry, 0620
Questions:
7
Year:
2016
Paper:
3
Variant:
1
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1
The diagram shows part of the Periodic Table. Li B Al C N O F Ne Na Si P S Cl Ar K Ca H Br Kr Cu Zn Answer the following questions using only the elements in the diagram. Each element may be used once, more than once or not at all. Which element has a smaller proton number than lithium, is formed at the cathode when a dilute solution of sulfuric acid is electrolysed, has an oxide of the type XO2 which is used to bleach wood pulp, forms ions which when tested with excess aqueous sodium hydroxide produce a white precipitate, is extracted from bauxite? Mercury has several naturally-occurring isotopes. One of these is shown. Hg What is the meaning of the term isotope? How many neutrons are there in one atom of the isotope Hg ? How many protons are there in one atom of the isotope Hg ? Determine the number of electrons in the mercury(ion, Hg2+.
2. Atoms, elements and compounds  →  2.2. Atomic structure and the Periodic Table
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2
The bar charts compare the concentrations of the main ions in two samples of seawater, sampleA and sampleB. Na+ Ca2+ K+ Mg2+ SiO3 2– Cl – HCO3 – concentration in mg / dm3 Na+ Ca2+ K+ Mg2+ SiO3 2– Cl – HCO3 – sample B concentration in mg / dm3 sample A Use the information in the bar charts to answer the following questions. Describe two differences in the composition of the seawater in sampleA and sampleB. Which positive ion has the lowest concentration in sample A? Calculate the mass of sodium ions in 200 cm3 of sample B. Show all your working. [1 dm3 = 1000 cm3] mass = mg Describe a test for sodium ions. test result River water contains small particles of clay. When these particles are viewed under a microscope they show a random, jumpy motion even when the water is still. What name is given to this type of movement? Carbon dioxide dissolves in water to form a mixture which contains hydrogencarbonate ions and hydrogen ions. CO2+ H2OHCO3 –+ H+What is the meaning of the symbol ? The solution formed is slightly acidic. Describe how you would use Universal Indicator paper to determine the pH of this solution. Carbon dioxide is a greenhouse gas which causes climate change. Explain how carbon dioxide contributes to climate change. State the name of one other greenhouse gas and give one source of this gas. gas source
12. Experimental techniques and chemical analysis  →  12.5. Identification of ions and gases
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Calcium is in Group II of the Periodic Table. Draw a diagram to show the electronic structure of an atom of calcium. Calcium is manufactured by the electrolysis of molten calcium chloride. Complete the boxes in the diagram to show the • anode, • cathode, • electrolyte. + − calcium forming Calcium reacts with water to form calcium hydroxide and a gas which ‘pops’ with a lighted splint. Complete the chemical equation for this reaction. Ca + H2O → Ca(OH)2 + Describe the manufacture and uses of lime (calcium oxide). Include at least one relevant word equation relating to the manufacture or use of lime.
4. Electrochemistry  →  4.1. Electrolysis
12. Experimental techniques and chemical analysis  →  12.5. Identification of ions and gases
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A porous pot has tiny holes in its walls which allow gases to move in or out of the pot. A teacher filled a porous pot with green chlorine gas. The teacher then placed the pot in a large jar of air. After 10 minutes, a green colour was seen outside the porous pot. chlorine gas air porous pot at the start after 10 minutes Use the kinetic particle model of matter to explain this observation. A porous barrier can be used to separate uranium fluoride molecules containing different isotopes of uranium. State the main use of the radioactive isotope 235U. Give one medical use of radioactive isotopes. The accurate relative atomic mass of uranium is 238.03. Define the term relative atomic mass. Chlorine reacts with potassium bromide to form bromine and potassium chloride. Complete the chemical equation for this reaction. + 2KBr → Br2 + KCl Give one use of chlorine. Chlorine forms an oxide with the formula Cl 2O7. Is this oxide an acidic or a basic oxide? Explain your answer. A teacher heated a test-tube containing anhydrous copper(chloride. A piece of damp litmus paper was placed at the top of the test-tube. heat litmus paper anhydrous copper(chloride The anhydrous copper(chloride decomposed and chlorine was formed. Describe the colour change of the litmus paper.
12. Experimental techniques and chemical analysis  →  12.5. Identification of ions and gases
9. Metals  →  9.4. Reactivity series
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The table shows the properties of some steels. steel percentage of carbon in the steel relative strength melting point range / °C ease of corrosion A 1.0 8.0 1430–1460 corrodes easily B 0.50 6.5 1430–1450 corrodes fairly easily C 0.25 5.0 1410–1430 corrodes fairly easily D 0.10 4.0 1440–1450 resistant to corrosion Use the information in the table to answer the following questions. What is the relationship between the percentage of carbon in the steel and its strength? State whether there is a relationship between the percentage of carbon in the steel and its melting point range. Explain your answer. Which steel would be best to use for making a bicycle chain? Explain your answer. Steel is an alloy. Which one of the diagrams best represents an alloy? Draw a ring around the correct answer. Cr Fe Fe Fe Fe Fe Cr Fe Ni Fe Fe Fe Fe Fe Ni Fe Cr Ni A Fe Fe Fe Fe Ni Ni Ni Ni Fe Cr Cr Cr Cr Fe Fe Fe Fe Cr B Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe Fe C Ni Ni Ni Ni Ni D Ni Ni Ni Ni Ni Ni Ni Ni Ni Ni Ni Ni Ni High voltage electricity cables are made from aluminium with a steel core. Apart from conducting electricity, what is the purpose of the steel core? Aluminium is a good electrical conductor. Give one other use of aluminium and state a property of aluminium which makes it suitable for this use. use property Aluminium powder reacts with powdered iron(oxide. The equation for this reaction is shown. 2Al + Fe2O3 → Al 2O3 + 2Fe Which substance is oxidised in this reaction? Explain your answer. The energy level diagram for this reaction is shown. energy 2Al + Fe2O3 Al 2O3 + 2Fe Is this reaction exothermic or endothermic? Explain your answer.
9. Metals  →  9.2. Uses of metals
9. Metals  →  9.3. Alloys and their properties
9. Metals  →  9.5. Corrosion of metals
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Describe the characteristic properties of acids. In your answer you should refer to the reactions of acids with metals, bases, carbonates and indicators. The table shows some properties of the first five members of the carboxylic acid homologous series. acid molecular formula melting point / °C boiling point / °C density in g / cm3 methanoic acid CH2O2 1.22 ethanoic acid C2H4O2 1.05 propanoic acid C3H6O2 –21 0.99 butanoic acid C4H8O2 –5 0.96 pentanoic acid C5H10O2 –34 0.93 How does the density of the carboxylic acids vary with the number of carbon atoms in the molecule? Suggest a value for the boiling point of pentanoic acid. Determine the state of ethanoic acid at 15 °C. Explain your answer. Draw the structure of the functional group present in carboxylic acids. Show all of the atoms and all of the bonds. Calculate the relative molecular mass of butanoic acid. Show all your working. Identify the following as either physical changes or chemical changes by writing either ‘physical’ or ‘chemical’ in the spaces provided. The condensation of ethanoic acid vapour to liquid ethanoic acid is a change. The reaction of sodium with ethanoic acid is a change. The dissolving of a salt in water is a change.
7. Acids, bases and salts  →  7.1. The characteristic properties of acids and bases
11. Organic chemistry  →  11.7. Carboxylic acids
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The diagram shows the changes of state when sulfur is heated. solid sulfur A liquid sulfur sulfur vapour B Give the names of the changes of state labelled A and B. A B Describe the arrangement and motion of the particles in sulfur vapour. arrangement motion Give one use of sulfur. Some compounds of sulfur are found in coal. Explain why the presence of sulfur in coal has an adverse effect on human health when the coal is burnt. One of the compounds of sulfur in coal is thiophene. The structure of thiophene is shown. C C C C S H H H H Determine the formula of thiophene. Thiophene can be made in the laboratory by heating ethyne, C2H2, with hydrogen sulfide, H2S, in the presence of a catalyst. What is the purpose of the catalyst? When 2.6 g of ethyne react with excess hydrogen sulfide, 4.2 g of thiophene are formed. Calculate the mass of thiophene formed when 15.6 g of ethyne react with excess hydrogen sulfide.
6. Chemical reactions  →  6.3. Reversible reactions and equilibrium
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