The gas phase decomposition of hydrogen iodide at 700 K HI (g) ½ H2 (g) + ½ I2 (g) is second order in HI with a rate constant of 1.20*10-3 M-1 s-1. If the initial concentration of HI is 1.09 M, the concentration of HI will be M after 2.36*103 seconds have passed.

C HI = 0.2667 M

Explanation:

HI (g) → 1/2H2 (g) + 1/2I2 (g)

decomposition rate HI (g):

∴ a: HI (g)

- ra = (K) * (Ca) ∧α

∴ K = 1.20 E-3 M/s ... rate constant

∴ α = 2 ... second order

∴ Cao = 1.09 M ... initial concentration of HI (g)

⇒ Ca = ? ... t = 2.36 E3 s

⇒ - ra = δCa/δt = K Ca²

⇒ - ∫δCa/Ca² = K∫δt

⇒ [ 1/Ca - 1/Cao ] = K*t

⇒ 1/Ca = (K*t) + 1/Cao

⇒ 1/Ca = ((1.20 E-3/M. s) (2.36 E3 s)) + (1/1.09 M)

⇒ 1/Ca = 2.832/M + 0.9174/M

⇒ 1/Ca = 3.749/M

⇒ Ca = 0.2667 M