Ammonia, NH3, is one of the most common inorganic chemicals used for the production of plastics,...

  

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Ammonia, NH3, is one of the most common inorganic chemicals used for the production of plastics, dyes, and pharmaceuticals. Production of ammonia includes methane reforming by steam, yielding hydrogen (Reaction 4-1). That hydrogen is then used to synthesise ammonia (Reaction 4-2). (a) CH4(g) + HO(g) = CO(g) + 3H2(g) H2(g) + 3N2(g) 2NH3(g) Use values of AH and AS for individual gases provided in Table 4-1 to answer the questions below. Assume the values do not change with temperature. (Reaction 4-1) (Reaction 4-2) Table 4-1. Standard thermochemical properties at 298 K Gas AH (kJ/mol) AS (J/K-mol) CH4 HO CO H N NH3 -74.85 -241.82 -110.54 0 0 -46.11 186.27 188.72 197.90 130.59 191.50 192.34 (b) (i) (ii) (iii) (iv) (i) (ii) Calculate the values of A,H for Reactions 4-1 and 4-2. Present these values per mole of H(g). Calculate the standard enthalpy change for the net reaction (i.e., the production of ammonia and carbon monoxide from methane, water vapour, and nitrogen) and state whether the net process is endothermic or exothermic. Determine the temperature at which neither reactants nor products would predominate for EACH reaction. State the range of temperatures where the products would predominate in EACH reaction. Sketch a plot of Gibbs free energy per mol of H versus temperature for Reactions 4-1 and 4-2. Extend the x-axis to 0 K. Label both axes, and show the axes' origins. Label the y-intercept for both lines. Ensure slopes of both lines have the correct sign and magnitude. Explain using thermodynamic concepts why the two steps of ammonia production should be run in separate reactors if the reactions are run at a standard state. Ammonia, NH3, is one of the most common inorganic chemicals used for the production of plastics, dyes, and pharmaceuticals. Production of ammonia includes methane reforming by steam, yielding hydrogen (Reaction 4-1). That hydrogen is then used to synthesise ammonia (Reaction 4-2). (a) CH4(g) + HO(g) = CO(g) + 3H2(g) H2(g) + 3N2(g) 2NH3(g) Use values of AH and AS for individual gases provided in Table 4-1 to answer the questions below. Assume the values do not change with temperature. (Reaction 4-1) (Reaction 4-2) Table 4-1. Standard thermochemical properties at 298 K Gas AH (kJ/mol) AS (J/K-mol) CH4 HO CO H N NH3 -74.85 -241.82 -110.54 0 0 -46.11 186.27 188.72 197.90 130.59 191.50 192.34 (b) (i) (ii) (iii) (iv) (i) (ii) Calculate the values of A,H for Reactions 4-1 and 4-2. Present these values per mole of H(g). Calculate the standard enthalpy change for the net reaction (i.e., the production of ammonia and carbon monoxide from methane, water vapour, and nitrogen) and state whether the net process is endothermic or exothermic. Determine the temperature at which neither reactants nor products would predominate for EACH reaction. State the range of temperatures where the products would predominate in EACH reaction. Sketch a plot of Gibbs free energy per mol of H versus temperature for Reactions 4-1 and 4-2. Extend the x-axis to 0 K. Label both axes, and show the axes' origins. Label the y-intercept for both lines. Ensure slopes of both lines have the correct sign and magnitude. Explain using thermodynamic concepts why the two steps of ammonia production should be run in separate reactors if the reactions are run at a standard state.

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Ammonia Production Calculations a Enthalpy Change Calculations i Enthalpy change per mole of H2g Rea... View the full answer