0620_m15_qp_22
A paper of Chemistry, 0620
Questions:
8
Year:
2015
Paper:
2
Variant:
2
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1
The diagram shows the structures of some substances containing carbon. A B C D E F O C O H C H H H H C H Ca2+ CO3 2– CO3 2– CO3 2– CO3 2– CO3 2– CO3 2– CO3 2– CO3 2– Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ C Cl Cl Cl Cl C C H H H C H H H Answer the following questions about these substances. Each substance may be used once, more than once or not at all. Which substance, A, B, C, D, E or F is a saturated hydrocarbon, has an ionic structure, is a product of respiration, is in the same homologous series as methane, is used for cutting? Substance D is an element. Explain why substance D is an element.
11. Organic chemistry  →  11.2. Naming organic compounds
11. Organic chemistry  →  11.3. Fuels
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2
Some properties of the halogens are shown in the table. halogen boiling point / °C state at room temperature and pressure fl uorine –188 chlorine –35 gas bromine +59 liquid iodine +184 solid astatine solid Use the information in the table to deduce the boiling point of astatine, the state of fl uorine at room temperature and pressure. When chlorine reacts with aqueous potassium iodide, the solution turns brown. Write a word equation for this reaction. Explain why iodine does not react with aqueous potassium chloride. When sodium reacts with iodine, energy is released. What is the name given to a reaction which releases energy? Explain what happens in terms of electron transfer when a sodium atom reacts with an iodine atom.
8. The Periodic Table  →  8.3. Group VII properties
11. Organic chemistry  →  11.5. Alkenes
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3
The diagram shows a limestone column in an industrial town. Limestone is largely calcium carbonate. column when first built the same column after 40 years iron pins Describe and explain the changes to the column over 40 years. In your answer refer to • the change to the limestone, • the name of a pollutant causing this change, • the chemistry involved in this change. The sections of the column are joined with iron pins which rust when exposed to the atmosphere. Describe two methods of rust prevention and explain how they prevent rusting. Iron is a transition element. Give two properties of transition elements that make them different from non-transition metals such as magnesium. An isotope of iron has 58 nucleons. Complete the table to show • the number of electrons and neutrons in this isotope of iron, • the relative charges on each particle. particle number of each particle present relative charge on the particle electron neutron no charge proton Iron reacts with hydrochloric acid to form iron(chloride and a gas which ‘pops’ with a lighted splint. Complete the symbol equation for this reaction. Fe + HCl → FeCl 2 +
9. Metals  →  9.6. Extraction of metals
9. Metals  →  9.4. Reactivity series
8. The Periodic Table  →  8.4. Transition elements
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4
Ammonium phosphate, (NH4)3PO4, is a fertiliser. Which two elements in ammonium phosphate are important for plant growth? and Aqueous ammonium phosphate can be made in the laboratory by reacting aqueous ammonia with aqueous phosphoric acid. aqueous phosphoric acid flask A aqueous ammonia State the name of the piece of apparatus labelled A. Suggest the pH value of aqueous phosphoric acid. Describe how the pH of the mixture in the fl ask changes as the acid is added. Which one of the following best describes the reaction of aqueous ammonia with aqueous phosphoric acid? Put a ring around the correct answer. combustion decomposition neutralisation reduction When sodium hydroxide is added to ammonium phosphate, ammonia is released. Complete the symbol equation for this reaction. (NH4)3PO4 + 3NaOH → Na3PO4 + NH3 + 3
12. Experimental techniques and chemical analysis  →  12.5. Identification of ions and gases
7. Acids, bases and salts  →  7.1. The characteristic properties of acids and bases
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5
The table shows the concentration of some ions present in a sample of seawater. name of ion formula of ion concentration in g / dm3 bromide Br – 0.06 calcium Ca2+ 0.30 chloride Cl – 20.00 I– 0.04 magnesium Mg2+ 1.00 potassium K+ 0.50 sodium Na+ 11.00 sulfate SO4 2– 0.80 Which positive ion in the table has the lowest concentration? Give the name of the ion with the formula I–. Which two ions in the table are formed from elements in Group II of the Periodic Table? and Give the names of two ions in the table which move towards the anode (positive electrode) when a sample of this seawater is electrolysed. and Sodium chloride can be extracted from seawater. Concentrated aqueous sodium chloride is electrolysed using the apparatus shown. + – graphite anode concentrated aqueous sodium chloride graphite cathode battery Suggest why the anode and cathode are made of graphite. Give the name of the product formed at the cathode (negative electrode). Chlorine is formed at the anode. Complete the electronic structure of a chlorine molecule. Show only the outer shell electrons. Cl Cl Molten magnesium bromide is electrolysed. Predict the products at the anode (positive electrode) and cathode (negative electrode). anode cathode
4. Electrochemistry  →  4.1. Electrolysis
12. Experimental techniques and chemical analysis  →  12.5. Identification of ions and gases
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6
Zinc oxide is used for making baby soap and cream for treating sunburn. Suggest why the zinc oxide used for these purposes needs to be pure. Zinc oxide can be reduced by carbon. Carbon monoxide is one of the products. What is the meaning of the term reduction? Write a word equation for the reaction of zinc oxide with carbon. Explain why, in the laboratory, the reaction should be carried out in a fume cupboard. The table shows how easy it is to reduce various metal oxides by heating with carbon. metal oxide ease of reduction with carbon lead oxide easily reduced at 300 °C magnesium oxide not reduced at 900 °C nickel oxide easily reduced at 500 °C zinc oxide fairly easily reduced at 900 °C Use the information in the table to put the metals in order of their reactivity. least reactive most reactive Zinc oxide reacts with sulfuric acid. Complete the word equation for this reaction. zinc oxide + sulfuric acid → zinc sulfate + Pure dry crystals of zinc sulfate can be made by the reaction of dilute sulfuric acid with excess zinc. How is excess zinc removed from the reaction mixture? Describe how you would obtain pure dry crystals of zinc sulfate from an aqueous solution of zinc sulfate. Zinc sulfate can be made from the reaction of sulfuric acid with zinc oxide or zinc. Give the name of another compound that reacts with sulfuric acid to produce zinc sulfate. A student reacts zinc with excess sulfuric acid. She obtains 16.1 g of zinc sulfate from 6.5 g of zinc. Calculate the mass of zinc sulfate she would obtain from 26.0 g of zinc. Calculate the relative formula mass of zinc sulfate, ZnSO4.
9. Metals  →  9.4. Reactivity series
9. Metals  →  9.5. Corrosion of metals
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7
Petroleum is separated into useful fractions by fractional distillation. kerosene fraction T gasoline fraction refinery gas fractions fuel oil lubricating fraction petroleum bitumen diesel oil Put an X on the diagram to show where the temperature in the column is the highest. Give the name of the fraction labelled T. The lubricating fraction is used to make lubricants. Give one other use of this fraction. Each fraction contains alkanes. Which two of the following statements are correct? Tick two boxes. Alkanes burn to form carbon dioxide and hydrogen. Ethene is an alkane with two carbon atoms. Alkanes polymerise to form poly. Alkanes are generally unreactive apart from burning. Methane is an alkane present in natural gas. Hydrogen can be made by cracking. What is meant by the term cracking? Complete the equation for the cracking of propane. C3H8 → + H2 Ethanol is formed by the catalytic addition of steam to ethene. Complete the structures of ethene and ethanol in the equation below, showing all atoms and bonds. + ethene H H C ethanol H H C H O H H What does the symbol mean?
11. Organic chemistry  →  11.3. Fuels
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8
A student placed a crystal of purple potassium manganate(on a fi lter paper which had been soaked in water. After 5 minutes, a purple colour had spread out from the crystal. After 30 minutes, the purple colour had spread further out. crystal of potassium manganate(at the start after 5 minutes after 30 minutes wet filter paper Use the kinetic particle theory to explain these observations. Describe the closeness and motion of the particles in a crystal of potassium manganate(. closeness motion Mixtures of dyes can be separated by paper chromatography using the apparatus shown below. base line On the diagram above • draw a line to show the solvent level at the beginning of the experiment, • put a cross to show where the spot of dye mixture is placed at the beginning of the experiment.
12. Experimental techniques and chemical analysis  →  12.3. Chromatography
1. States of matter  →  1.1. Solids, liquids and gases
1. States of matter  →  1.2. Diffusion
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