0620_s08_qp_2
A paper of Chemistry, 0620
Questions:
7
Year:
2008
Paper:
2
Variant:
0
Login to start this paper & get access to powerful tools
1
For Examiner's Use The diagram shows the structures of some substances containing carbon. O C O C C H H H H C H H H H C C O H H H H H H 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 C C C C C C C C Ca2+ CO2– Ca2+ CO2– CO2– Ca2+ Ca2+ CO2– CO2– Ca2+ Ca2+ CO2– Ca2+ CO2– CO2– Ca2+ Ca2+ CO2– CO2– Ca2+ A B C D E F Answer these questions using the letters A, B, C, D, E or F. Which one of these structures is ionic? Which one of these structures represents ethanol? Which one of these structures represents a gas which turns limewater milky? Which one of these structures is an unsaturated hydrocarbon? Describe a chemical test for an unsaturated hydrocarbon. test result For Examiner's Use State the chemical name of structure B. Structure F has several uses. Which one of the following is a correct use of structure F? Tick one box. for cutting metals as a lubricant for filling balloons as an insulator The structures A to E are compounds. What do you understand by the term compound? State the type of bonding in structure A.
11. Organic chemistry  →  11.2. Naming organic compounds
11. Organic chemistry  →  11.1. Formulae, functional groups and terminology
Open
2
For Examiner's Use The diagram shows a statue in a park in an industrial town. The statue is made from limestone. iron pins inside statue statue when first erected the same statue after 20 years State the name of the chemical present in limestone. Use ideas about the chemistry of atmospheric pollutants to suggest how and why the statue changes over 20 years. Parts of the statue are joined together with iron pins. After 30 years, the arm falls off the statue. Suggest why the arm falls off. For Examiner's Use Iron has several isotopes. What do you understand by the term isotopes? The table shows the number of subatomic particles in an atom of iron. type of particle number of particles relative charge on the particle electron neutron proton Complete the table to show the relative charge on each particle. State the number of nucleons in this isotope of iron. Some isotopes are radioactive. State one industrial use of radioactive isotopes. Iron reacts with very dilute nitric acid. Fe + 2HNO3 Fe(NO3)2 + H2 Write a word equation for this reaction.
6. Chemical reactions  →  6.4. Redox
9. Metals  →  9.4. Reactivity series
9. Metals  →  9.6. Extraction of metals
Open
3
For Examiner's Use The table shows the concentration of some ions present in seawater. name of ion formula of ion concentration of ion in g / dm3 bromide Br – 0.07 calcium Ca2+ 0.4 chloride Cl – 19.1 magnesium Mg2+ 1.2 potassium K+ 0.3 sodium Na+ 10.6 − SO 0.8 Which negative ion has the highest concentration in seawater? State the name of the ion with the formula − SO . Which two ions in the table are formed from Group I elements? and When seawater is evaporated a number of different compounds are formed. State the name of the compound which is present in the greatest quantity. State the names of two ions in the table which move to the cathode when seawater is electrolysed. and For Examiner's Use When concentrated seawater is electrolysed, chlorine is formed at one of the electrodes. To which Period in the Periodic Table does chlorine belong? Draw the electronic structure of a chlorine molecule. Show only the outer electrons. Drinking water can be obtained by purifying seawater. Explain why distillation rather than filtration is used to purify seawater for drinking.
12. Experimental techniques and chemical analysis  →  12.5. Identification of ions and gases
4. Electrochemistry  →  4.1. Electrolysis
Open
4
For Examiner's Use The diagram shows a water treatment works. water in to homes chlorine added aluminium sulphate added sedimentation tank sand filter State one use of water in industry. Explain how the sand filter helps purify the water. The aluminium ions in aluminium sulphate cause clay particles to clump together. Describe a test for aluminium ions. test result Why is chlorine added to the water? For Examiner's Use Chlorine is in Group VII of the Periodic Table. When chlorine reacts with a solution of potassium bromide, the solution turns a reddish – brown colour. Write a word equation for this reaction. Explain why iodine does not react with a solution of potassium bromide. When chlorine reacts with sodium to form sodium chloride, energy is released. State the name given to a reaction which releases energy. What type of bonding is present in sodium chloride? Explain what happens in terms of electron transfer when a sodium atom reacts with a chlorine atom.
9. Metals  →  9.4. Reactivity series
11. Organic chemistry  →  11.4. Alkanes
12. Experimental techniques and chemical analysis  →  12.5. Identification of ions and gases
Open
5
For Examiner's Use Pure dry crystals of magnesium sulphate can be made by reacting excess magnesium powder with dilute sulphuric acid. During the reaction, bubbles of a colourless gas are given off. State the name of this gas. Why is excess magnesium used? How is the excess magnesium removed from the reaction mixture? Describe how you can obtain pure dry crystals of magnesium sulphate from a solution of magnesium sulphate. Describe one other reaction that makes magnesium sulphate. Write a word equation for the reaction you suggested in part . Magnesium sulphate can be used as a medicine. Explain why the chemicals used in medicines need to be as pure as possible. For Examiner's Use A student repeats the experiment using excess sulphuric acid. She obtains 24 g of magnesium sulphate from 4.8 g of magnesium. How much magnesium sulphate can the student obtain from 1.2 g of magnesium? A sample of 20 g of impure magnesium sulphate contains 19.5 g of magnesium sulphate. Calculate the percentage purity of the magnesium sulphate.
7. Acids, bases and salts  →  7.3. Preparation of salts
9. Metals  →  9.4. Reactivity series
Open
6
For Examiner's Use Petroleum is separated into useful fractions by distillation. petroleum fuel gas fractions petrol paraffin diesel lubricating fraction bitumen What do you understand by the term fraction? Which fraction has the lowest boiling point? Describe how distillation is used to separate these fractions. State a use for the paraffin fraction, the bitumen fraction. For Examiner's Use Ethene can be made by cracking certain hydrocarbon fractions. Explain what is meant by the term cracking. Complete the equation for the cracking of tetradecane, C14H30. C14H30 + C2H4 Ethanol is formed when steam reacts with ethene at high pressure and temperature. A catalyst of phosphoric acid is used. ethene + steam ethanol What is the function of the catalyst? What is the meaning of the symbol ? Ethanol is also formed when yeast grows in sugar solution. What is this process called? Put a ring around the correct answer. addition combustion fermentation neutralisation Phosphoric acid is a typical acid. State what you would observe when a solution of phosphoric acid is added to blue litmus, a solution of sodium carbonate.
11. Organic chemistry  →  11.3. Fuels
11. Organic chemistry  →  11.6. Alcohols
Open
7
For Examiner's Use A student placed a crystal of copper(sulphate in a beaker of water. After one hour the crystal had completely disappeared and a dense blue colour was observed in the water at the bottom of the beaker. After 48 hours the blue colour had spread throughout the water. water copper(sulphate crystal after 1 hour after 48 hours Use the kinetic particle theory to explain these observations. Describe the arrangement and motion of the particles in the copper(sulphate crystal. arrangement motion Copper ions can be separated from other metal ions by paper chromatography. Draw a labelled diagram of the apparatus for paper chromatography. In your diagram include • the solvent, • the spot where the solution containing copper ions is placed. For Examiner's Use Copper can be purified by electrolysis. impure copper foil pure copper foil copper(sulphate solution + – Choose a word from the list below which describes the pure copper foil. Put a ring around the correct answer. anion anode cathode cation electrolyte Describe what happens during this electrolysis to the pure copper foil, the impure copper foil.
4. Electrochemistry  →  4.1. Electrolysis
12. Experimental techniques and chemical analysis  →  12.5. Identification of ions and gases
Open