Question

For the chemical equation SO2(g) + NO2(g) → SO2(g) + NO(g) the equilibrium constant at a certain temperature is 2.70. At this temperature, calculate the number of moles of NO, (g) that must be added to 2.99 mol SO,(g) in order to form 1.30 mol S03(g) at equilibrium. moles of NO2(g): mol

Answer 1

The given equilibrium is SO2 (g) + NO2 (g) = S03 (g) + NO (g) Let the volume of the system = 1 L Let the initial moles of NO, (to be added) = n Concentration of NO, = n moles/1L = n M Let x be the change in the conc. of each species at equilibrium soz (g) + NO (g) so2(g) + NO2 (g) 2.99 Initial change 1 -x -x Equilibrium 2.99-X n-x Given that the number of moles of soz = 1.30 mol So x = 1.30 (SO3) = moles/volume = 1.30 mol/1L = 1.30 M Number of moles of NO = x = 1.30 [NO] = 1.30 mol/1.0 L = 1.30 M Number of moles of s02 = 2.99 - x = 2.99 – 1.30 = 1.69 mol (SO2] = 1.69 mol/1L = 1.69 M Number of moles of NO, = n-x= n - 1.30 [NO2) = (n - 1.30) M Given that equilibrium constant = 2.70 _[SO3][NO] - = 2.70 seg [SO,][NO] 1.30x1.30 =2.70 1.69x(n-1.30) 1.69 1.69X2 70 =(n-1.30) >n-1.30 = = 0.37037 2.70 n=1.30+0.37037 =1.67037 = 1.67 Number of moles of NO, gas to be added =1.67 mol