0620_w11_qp_22
A paper of Chemistry, 0620
Questions:
7
Year:
2011
Paper:
2
Variant:
2
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1
For Examiner’s Use The diagram shows fi ve different pieces of laboratory glassware, A, B, C, D and E. A B C D E Choose from A, B, C, D or E to answer the following questions. Each letter may be used once, more than once or not at all. Which piece of glassware is best used to measure out a volume of liquid accurately, place a spot of liquid on chromatography paper, condense a liquid with a low boiling point, shake two solutions together to mix them, deliver a variable volume of solution when performing a titration? For Examiner’s Use The diagram shows the apparatus used to prepare carbon dioxide in the laboratory. pieces of calcium carbonate water concentrated hydrochloric acid delivery tube gas jar State the name of a rock which is made up largely of calcium carbonate. Which one of these statements about carbon dioxide is correct? Tick one box. Carbon dioxide is lighter than air. Carbon dioxide is a liquid at room temperature. Carbon dioxide is heavier than air. Carbon dioxide has the same density as air. Complete the equation for the reaction of calcium carbonate with hydrochloric acid. CaCO3 + HCl → CaCl 2 + CO2 +
12. Experimental techniques and chemical analysis  →  12.1. Experimental design
12. Experimental techniques and chemical analysis  →  12.5. Identification of ions and gases
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2
For Examiner’s Use Many of the elements in the Periodic Table are metals. State one common use for each of the following metals. copper platinum aluminium Lead is a metal in Group IV of the Periodic Table. State one adverse effect of lead on health. Lead has several isotopes. One isotope of lead is 207Pb State the number of protons and neutrons in this isotope of lead. number of protons number of neutrons Sodium is a very reactive metal. A student added a few drops of litmus solution to a large beaker of water. She then dropped a small piece of sodium into the beaker. Describe what the student would observe during the reaction. Complete the word equation for the reaction of sodium with water. sodium + water → + For Examiner’s Use Sodium chloride is formed when sodium burns in chlorine. Sodium chloride is an ionic compound. Complete the following sentences about this reaction using words from the list. electron gains ion loses molecule negative positive proton When sodium burns in chlorine, each sodium atom loses an and becomes a sodium . Each chlorine atom an electron and becomes a ion.
9. Metals  →  9.4. Reactivity series
12. Experimental techniques and chemical analysis  →  12.5. Identification of ions and gases
4. Electrochemistry  →  4.1. Electrolysis
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3
For Examiner’s Use Hydrogen peroxide decomposes slowly at room temperature to form water and oxygen. The reaction is catalysed by manganese(oxide. 2H2O2 → 2H2O + O2 A student used the apparatus shown below to study how changing the concentration of hydrogen peroxide affects the speed of this reaction. hydrogen peroxide manganese(oxide gas syringe oxygen collects here Apart from the volume of hydrogen peroxide, state two things that the student must keep the same in each experiment. 1. 2. For Examiner’s Use The student measured the volume of oxygen produced using three different concentrations of hydrogen peroxide. The results are shown on the graph below. time / s volume of oxygen / cm3 concentration of hydrogen peroxide in g / dm3 A B C Describe how the speed of the reaction varies with the concentration of hydrogen peroxide. Explain why the fi nal volume of oxygen given off is less for graph B than for graph A. From the graph, determine the time taken for the reaction to be completed when 3 g / dm3 hydrogen peroxide (line A) was used. the volume of oxygen produced by 2 g / dm3 hydrogen peroxide (line B) in the fi rst 15 seconds. For Examiner’s Use The student then tested various compounds to see how well they catalysed the reaction. He used the same concentration of hydrogen peroxide in each experiment. The table shows the time taken to produce 20 cm3 of oxygen using each compound as a catalyst. compound time taken to produce 20 cm3 of oxygen / s copper(oxide lead(oxide magnesium oxide did not produce any oxygen manganese(oxide Put these compounds in order of their effectiveness as catalysts. worst catalyst best catalyst
6. Chemical reactions  →  6.2. Rate of reaction
6. Chemical reactions  →  6.3. Reversible reactions and equilibrium
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4
For Examiner’s Use Natural gas and the hydrocarbons obtained from the distillation of petroleum are important fuels. State the name of the main substance present in natural gas. Petroleum is a thick liquid. Describe the liquid state in terms of ● how close the particles are to each other, ● the arrangement of the particles, ● the movement of the particles. The diagram shows a distillation column used to separate petroleum into fractions. refinery gas fractions X kerosene Y fuel oil lubricating oil bitumen gasoline On the diagram, draw an arrow to show where the petroleum vapour enters the column. What do you understand by the term fraction? For Examiner’s Use In the diagram on page 9, two fractions have not been named. State the name of fraction X fraction Y One of the refi nery gases is ethane. Draw the structure of ethane showing all atoms and bonds. Which one of these phrases describes ethane correctly? Tick one box. Ethane is an unsaturated hydrocarbon. Ethane is a saturated hydrocarbon. Ethane polymerises to form poly. Ethane is an alkene.
11. Organic chemistry  →  11.3. Fuels
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5
For Examiner’s Use Match the phrases on the left with the defi nitions on the right. The fi rst one has been done for you. relative formula mass an atom that has become charged molecule the smallest part of an element which can take part in a chemical change atom two or more atoms covalently bonded together ion the sum of the relative atomic masses in a compound Sodium hydroxide, NaOH, is an ionic compound which dissolves in water to form a strongly alkaline solution. Which one of the following best describes the pH of a concentrated aqueous solution of sodium hydroxide? Put a ring around the correct answer. pH 2 pH 5 pH 7 pH 8 pH 13 Calculate the relative formula mass of sodium hydroxide. The equation describes how sodium hydroxide reacts with hydrochloric acid. NaOH + HCl → NaCl + H2O What type of chemical reaction is this? For Examiner’s Use A student used a syringe to add 1 cm3 portions of hydrochloric acid to an aqueous solution of sodium hydroxide. hydrochloric acid syringe sodium hydroxide solution Describe how the pH of the solution in the beaker changes as the hydrochloric acid is added until the acid is in excess. For Examiner’s Use The diagram shows the apparatus used to electrolyse concentrated aqueous sodium chloride. anode cathode concentrated aqueous sodium chloride gases + – Give a description of this electrolysis. In your description include ● what substance the electrodes are made from and the reason for using this substance ● what you would observe during the electrolysis ● the names of the substances produced at each electrode.
12. Experimental techniques and chemical analysis  →  12.5. Identification of ions and gases
4. Electrochemistry  →  4.1. Electrolysis
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6
For Examiner’s Use When coal is heated in the absence of air, coke is formed together with a gas called coal gas and a liquid which contains ammonia. Coke is largely carbon. State one use of coke in industry. Two other forms of carbon are diamond and graphite. Use your knowledge of the structure of diamond and graphite to explain why graphite is a good lubricant. why diamond is very hard. Give one use of diamond that depends on its hardness. The liquid which contains ammonia can be reacted with sulfuric acid. Complete the word equation for this reaction ammonia + sulfuric acid → Which one of the following elements do most fertilisers contain? Put a ring around the correct answer. chlorine nitrogen sodium sulfur Coal gas contains methane. Complete the diagram to show how the electrons are arranged in a molecule of methane. H H H H C For Examiner’s Use When coal is burnt, sulfur dioxide is given off. Which two of the following statements about sulfur dioxide are correct? Tick two boxes. Sulfur dioxide is an acidic oxide. About 20 % of the air is sulfur dioxide. Most of the sulfur dioxide in the air comes from car exhausts. Sulfur dioxide contributes to acid rain.
10. Chemistry of the environment  →  10.3. Air quality and climate
6. Chemical reactions  →  6.3. Reversible reactions and equilibrium
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7
For Examiner’s Use Ethanol, C2H5OH, is a member of the alcohol homologous series. Give two characteristics of a homologous series. 1. 2. Draw the structure of ethanol showing all atoms and bonds. One use of ethanol is as a solvent. A pupil studied the reaction of iodine with zinc. She fi rst dissolved a few crystals of iodine in ethanol and recorded the temperature of the solution. The temperature was 18 °C. She then added excess powdered zinc and recorded the temperature again. The new temperature was 37 °C. temperature 18 °C iodine dissolved in ethanol temperature 37 °C excess zinc Is this reaction endothermic or exothermic? Explain your answer. What colour is solid iodine? For Examiner’s Use The equation for the reaction is zinc + iodine → zinc iodide When the reaction is complete, the mixture contains zinc iodide dissolved in ethanol and unreacted zinc powder. Suggest how you can get crystals of zinc iodide from the reaction mixture. The diagram shows the structure of zinc iodide. I – I – I – I – I – I – Zn2+ Zn2+ Zn2+ Zn2+ Zn2+ I – I – I – I – What is the simplest formula for zinc iodide? The list below shows four different types of structure. What type of structure is zinc iodide? Put a ring around the correct answer. giant covalent giant ionic metallic molecular For Examiner’s Use The equation for the reaction of zinc with dilute nitric acid is 4Zn + 10HNO3 → 4Zn(NO3)2 + NH4NO3 + 3H2O Write a word equation for this reaction. Describe a test for ammonium ions. test result
9. Metals  →  9.4. Reactivity series
11. Organic chemistry  →  11.5. Alkenes
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