AQA Jun 2010 Paper 4 Q4

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do not write outside the box in some food products containing pork were withdrawn from sale because tests showed that they contained amounts of compounds called dioxins many times greater than the recommended safe levels dioxins can be formed during the combustion of chlorine containing compounds in waste incinerators dioxins are very unreactive compounds and can therefore remain in the environment and enter the food chain many dioxins are polychlorinated compounds such as tetrachlorodibenzodioxin tcdd shown below cl cl cl cl in a study of the properties of dioxins tcdd and other similar compounds were synthesised the mixture of chlorinated compounds was then separated before each compound was identified by mass spectrometry a fractional distillation is not a suitable method to separate the mixture of chlorinated compounds before identification by mass spectrometry suggest how the mixture could be separated mark b the molecular formula of tcdd is c h o cl chlorine exists as two isotopes cl and cl deduce the number of molecular ion peaks in the mass spectrum of tcdd and calculate the m z value of the most abundant molecular ion peak number of molecular ion peaks m z value of the most abundant molecular ion peak marks c suggest one operating condition in an incinerator that would minimise the formation of dioxins mark wmp jun chem do not write outside the box d tcdd can also be analysed using c n m r d i give the formula of the compound used as the standard when recording a c spectrum mark d ii deduce the number of peaks in the c n m r spectrum of tcdd mark turn over for the next question turn over wmp jun chem

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