Question

At 450 degrees celcius, 3.60 mol of ammonia is placed in

a2.00-L vessel and allowed to decompose to the elements.

If the experimental value of K is 6.3 for
thisreaction at this temperature, calculate the
equilibriumconcentration of each reagent. What is the total
pressure in theflask?

Answer 1

x = 12.4 atm

Step-by-step explanation:

step1: To calculate the pressure of NH3 in theflask using ideal gas equation

PV = nRT

Hence, we have

P = 3.60 mol * 0.0821L.atm / mol.K * (450 +273)K /2.00L

= 106.84 atm

step2: To calculate the equilibrium concentration of each component

2NH3 ↔ N2 + 3H2

initial(p) 106.84atm 0 0

change -2x +x +3x

equilibrium (106.84-2x ) x 3x

k = PN2 PH23 /PNH32

6.3 = x * (3x)3 / (106.84-2x ) 2

since k is small , we ignore 2x compared to 106.84

otherwise to get the exact value of x u have to solve the equation above

taking approx x = 12.4atm

then substitute the value of x in the respective equilibrium values

then find PT = PN2+ PH2+PNH3