Question

Phosphorus is an element commonly found in the infernal regions. It exists in various forms called allotropes. Consider the reaction at 1210 K :

P4(g) -->2P2(g)

(A) In a 4.0 L container, at 1210 Kelvin, an equilibrium mixture is found to consist of:

p(P4)=250.0 atm and p(P2)=1.40atm. Determine the value of the equilibrium constant, Kp , at thistemperature.

K p =

(B) Suppose that a new mixture of gases is produced also at 1210 K where: p(P4)=1.81*10^-3 and p(P2)=0.119atm.

Calculate the reaction quotient, Q;

Determine whether for these conditions, the reaction is spontaneous to the right (R); spontaneous to the left (L); or at equilibrium(E);

Calculate the value of Kc and calculate the value of deltaG.

Answer 1

A)

P4(g) ------------>2 P2(g)

250                      1.40 atm

Kp = P²_P2 / P_P4

       = 1.40^2 / 250

     = 7.84 x 10^-3

equilibrium constant, Kp = 7.84 x 10^-3

B)

Q = P²_P2 / P_P4

       = 0.119^2 / 1.81 x 10^-3

     = 7.82

reaction quotient, Q = 7.82.

here :

Q > K.

so the reaction is spontenous to the left.

If Q > K, the reverse reaction is favoured, the reaction moves from right to left.

Kp = Kc (RT)^Dn

7.84 x 10^-3 = Kc (0.0821 x 1210)^1

Kc = 7.89 x 10^-5