Question

Consider the decomposition of the compound C5H6O3 as follows below. C5H6O3(g) → C2H6(g) + 3 CO(g) When a 5.63-g sample of pure C5H6O3(g) was sealed into an otherwise empty 2.50 L flask and heated to 200.°C, the pressure in the flask gradually rose to 1.63 atm and remained at that value. Calculate K for this reaction.

Answer 1

Answer:

K = 6.5 × 10⁻⁶

Explanation:

C₅H₆O₃ ⇄ C₂H₆ + 3CO

Use PV=nRT to find the initial pressure of C₅H₆O₃

P (2.50) = (0.0493) (0.08206) (473)

P = 0.78atm

C₅H₆O₃ ⇄ C₂H₆ + 3CO

0.78atm      0           0

0.78 - x        x           3x

1.63atm = 0.78 - x + x + 3x

P(total) = 0.288atm

C₅H₆O₃ = 0.78 - 0.288

             = 0.489atm

C₂H₆ = 0.288atm

CO = 0.846atm

$K_p = \frac{0.288 * 0.864^3}{0.489}$

     = 0.379

$K = \frac{K_p}{RT^3}$

$K = \frac{0.379}{(0.0821 * 473)^3}$

   = 6.5 × 10⁻⁶