Chemistry Help Please!

Question

Part A. Phosgene (carbonyl chloride), COCl2, is an extremely toxic gas that is used in manufacturing certain dyes and plastics. Phosgene can be produced by reacting carbon monoxide and chlorine gas at high temperatures: CO(g)+Cl2(g)?COCl2(g).

Carbon monoxide and chlorine gas are allowed to react in a sealed vessel at 471°C. At equilibrium, the concentrations were measured and the following results obtained:

Gas          Partial Pressure (atm)
CO                    0.810
Cl2                     1.12

COCl2                0.280

 

**What is the equilibrium constant, Kp, of this reaction?**

 

 

Part B. The following reaction was performed in a sealed vessel at 756°C: H2(g)+I2(g)<->2HI(g).

Initially, only H2 and I2 were present at concentrations of [H2]=3.10M and [I2]=2.00M. The equilibrium concentration of I2 is 0.0700M. What is the equilibrium constant, Kc, for the reaction at this temperature?

Answer 1

 For the first one,

 

The Kp of a reaction can be found by the partial pressures of the products over reactants. Since this is a one to one mole ratio and the P.P.s are given; simply plug into the Kp formula

 

Kp= P[COCl2]/ [PCO][PCl2]

    = .280/0.81 x 1.12

    = 0.907

 

B) We see that I2 has lost 1.93M at eq, so therefor H2 will lose the same amount, and HI will gain double. The reason is that I2 and H2 are going toward eq, or starting off then reacting to produce 2 parts HI, so they will lose M as they approach eq. And HI will gain at eq.

 

[I2]initial=3.1 - 0.7 M concentration at eq = 1.93 loss

[H2]initial= 3.1 - 7.93M loss= 1.17 concentration at eq

[HI] initial= 0 (we haven't formed any product yet)

              =0 + 2(1.93) gained at eq.=3.86 at eq

 

So pluging into the Kc= C^c / A^axB^b

Kc=      [3.68]²

       [1.17][.07]

     = 181.92