A student mixes 5.00 mL of 2.00 x 10-3 M Fe(NO3)3 with 5.00 mL 2.00 x 10-3 M KSCN. She finds that in the equilibrium mixture the concentration of FeSCN+2 is 1.40 x 10-4 M.

a. What is the initial concentration in solution of the Fe+3 and SCN-?

b. What is the equilibrium constant for the reaction?

c. What happened to the K+ and the NO3- ions in this solution?

answer: the value of enthalpy change will be -152.80 kj.

solution:

pressure = 1atm , temperature = = 298 k

given that pressure and temperature are same in both gases , the number of moles of both gases can be determined by the ideal gas equation.

according to reaction 3 moles no are reacting with 1 mol of ,then 0.49 mol of no will react with moles of ozone that is 0.16 moles of ozone. since, no is limiting reagent and is an excessive reagent.

enthalpy change for the reaction between the given volumes of the gases is :