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UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS General Certificate of Education Advanced Subsidiary Level and Advanced Level
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May/June 2011 1 hour
CHEMISTRY Paper 1 Multiple Choice
Multiple Choice Answer Sheet Soft clean eraser Soft pencil (type B or HB is recommended) Data Booklet
READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, highlighters, glue or correction fluid. Write your name, Centre number and candidate number on the Answer Sheet in the spaces provided unless this has been done for you. There are forty questions on this paper. Answer all questions. For each question there are four possible answers A, B, C and D. Choose the one you consider correct and record your choice in soft pencil on the separate Answer Sheet. Read the instructions on the Answer Sheet very carefully. Each correct answer will score one mark. A mark will not be deducted for a wrong answer. Any rough working should be done in this booklet.
This document consists of 15 printed pages and 1 blank page. IB11 06_9701_11/4RP © UCLES 2011
2 Section A For each question there are four possible answers, A, B, C, and D. Choose the one you consider to be correct. 1
Which equation represents the second ionisation energy of an element X? A B C D X(g) → X2+(g) + 2e– X+(g) → X2+(g) + e– X(g) + 2e– → X2–(g) X–(g) + e– → X2–(g)
In flooded soils, like those used for rice cultivation, the oxygen content is low. In such soils, anaerobic bacteria cause the loss of nitrogen from the soil as shown in the following sequence. In which step is the change in oxidation number (oxidation state) of nitrogen different to the changes in the other steps? A NO3–(aq) NO2–(aq) B NO(g) C N2O(g) D N2(g)
In the extraction of aluminium by the electrolysis of molten aluminium oxide, why is cryolite added to the aluminium oxide? A B C D to ensure the aluminium is not oxidised to ensure the anode is not oxidised to lower the melting point of the aluminium oxide to prevent corrosion of the cathode
© UCLES 2011
3 4 Different Boltzmann distributions are shown in the diagrams. diagram 1 P number of molecules Q number of molecules diagram 2 X Y
In diagram 1, one curve P or Q corresponds to a temperature higher than that of the other curve. In diagram 2, one line X or Y corresponds to the activation energy for a catalysed reaction and the other line corresponds to the activation energy of the same reaction when uncatalysed. Which combination gives the correct curve and line? higher temperature A B C D 5 P P Q Q presence of catalyst X Y X Y
Which factor helps to explain why the first ionisation energies of the Group I elements decrease from lithium to sodium to potassium to rubidium? A B C D The nuclear charge of the elements increases. The outer electron is in an ‘s’ subshell. The repulsion between spin-paired electrons increases. The shielding effect of the inner shells increases.
© UCLES 2011
4 6 In the diagram, curve X was obtained by observing the decomposition of 100 cm3 of 1.0 mol dm–3 hydrogen peroxide, catalysed by manganese(IV) oxide. Y X
volume of oxygen formed
Which alteration to the original experimental conditions would produce curve Y? A B C D 7 adding some 0.1 mol dm–3 hydrogen peroxide adding water lowering the temperature using less manganese(IV) oxide
In the last century the Haber process was sometimes run at pressures of 1000 atm and higher. Now it is commonly run at pressures below 100 atm. What is the reason for this change? A B C D An iron catalyst is used. Maintaining the higher pressures is more expensive. The equilibrium yield of ammonia is increased at lower pressures. The rate of the reaction is increased at lower pressures.
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