12. Nitrogen and sulfur
A section of Chemistry, 9701
Listing 10 of 350 questions
Write equations to illustrate the reactions of the following oxides with water. phosphorus(oxide sulfur(oxide When NO2 reacts with water, nitrogen undergoes a disproportionation reaction in which one nitrogen atom decreases its oxidation number by 1 and another nitrogen atom increases its oxidation number by 1. A mixture of two acids results. Suggest an equation for the reaction between NO2 and water. In a similar disproportionation reaction, Cl O2 reacts with aqueous NaOH to produce a solution containing two chlorine-containing sodium salts. Suggest an equation for the reaction between Cl O2 and aqueous NaOH. The major source of sulfur for the manufacture of sulfuric acid by the Contact process is the de-sulfurisation of ‘sour’ natural gas. Many natural gas wells produce a mixture of volatile hydrocarbons (mainly CH4 and C2H6) together with up to 25% hydrogen sulfide, H2S. Complete and balance the following equation showing the complete combustion of a gaseous mixture consisting of 2 mol of CH4, 1 mol of C2H6 and 1 mol of H2S. 2CH4 + C2H6 + H2S + ______ SO2 + ______ + ______ Explain why it is important to remove the H2S before burning the natural gas industrially. The H2S is removed by passing the ‘sour’ natural gas through a solvent containing ethanolamine. The following reaction takes place. HOCH2CH2NH2 + H2SHOCH2CH2NH3 + + SH– If a sample of natural gas contains 5% by volume of H2S, calculate the mass of ethanolamine required to remove all the H2S from a 1000 dm3 sample of gas, measured under room conditions. The H2S can be recovered by warming the solution to 120 °C, when the above reaction is reversed. The ethanolamine can then be recycled. What type of reaction is occurring here? The recovered H2S is converted to sulfur by the following two reactions. I Part of the H2S is burned in air. H2S + 1.5O2 SO2 + H2O II The gas stream resulting from reaction I is then blended with the remaining H2S and fed into an iron oxide catalyst bed, where sulfur and water are produced according to the following equation. 2H2S+ SO23S+ 2H2OUse the following data to calculate ΔH o–– for the reaction between H2S and SO2. compound ΔH o–– f / kJ mol–1 H2S–21 SO2–297 H2O–242 S+11 ΔH o–– = kJ mol–1
9701_w10_qp_43
THEORY
2010
Paper 4, Variant 3
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