AQA Jun 2014 Paper 2 Q3

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do not write outside the box a antimony is a solid element that is used in industry the method used for the extraction of antimony depends on the grade of the ore antimony can be extracted by reacting scrap iron with low grade ores that contain antimony sulfide sb s a i write an equation for the reaction of iron with antimony sulfide to form antimony and iron ii sulfide mark a ii write a half equation to show what happens to the iron atoms in this reaction mark b in the first stage of the extraction of antimony from a high grade ore antimony sulfide is roasted in air to convert it into antimony iii oxide sb o and sulfur dioxide b i write an equation for this reaction mark b ii identify one substance that is manufactured directly from the sulfur dioxide formed in this reaction mark wmp jun chem do not write outside the box c in the second stage of the extraction of antimony from a high grade ore antimony iii oxide is reacted with carbon monoxide at high temperature c i use the standard enthalpies of formation in table and the equation given below table to calculate a value for the standard enthalpy change for this reaction table sb o s co g hf kj mol sb i co g sb o s co g sb i co g marks c ii suggest why the value for the standard enthalpy of formation of liquid antimony given in table is not zero mark c iii state the type of reaction that antimony iii oxide has undergone in this reaction mark d deduce one reason why the method of extraction of antimony from a low grade ore described in part a is a low cost process do not include the cost of the ore mark turn over wmp jun chem

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