Values of the equilibrium constant, Kp, are given below for the gas-phase hydrogenation reaction
2 HCN(g) + 4 H2(g) → 2 CH3NH2(g).
Kp (atm-4) : 1.8 x 1025, 5.5 x 10-3, 3.7 x 10-13
T(K): 300.0 , 600.0 , 900.0
Use the approach outlined in the handout 'How To Solve Equilibrium Problems' to solve the given problems associated to the hydrogenation reaction. Use partial pressure as the concentration unit for the gaseous species.
a) The reaction was performed at 300.0 K. A flask was filled with reagents so that the initial concentrations of H2, HCN, and CH3NH2 were 2.0 atm, 0.20 atm, and 0.00 atm respectively. Note that concentrations are given as partial pressures in atm. This is the conventional choice for gaseous species. Find out the equilibrium concentrations of the three species.
b) The reaction was repeated at 900.0 K with the same initial amount of material. The initial partial pressures of H2, HCN, and CH3NH2 were 6.0 atm, 0.60 atm, and 0.00 atm respectively. Why have the partial pressures increased? Re-compute the equilibrium concentrations of the three species.
c) The reaction was repeated at 300.0 K and the concentrations of H2, HCN, and CH3NH2 were 2.0 atm, 0.20 atm and 1.00 atm respectively. Find out the equilibrium concentrations of the three species.
d) Would the calculation still be straightforward if the reaction were conducted at 600.0 K? In brief describe.