it is on chemistry

Question

The half-life for the second-order decomposition of HI according to the chemical equation: 2HI (g)  → H₂ (g) + I₂(g) is 10.5 s when the initial concentration of HI is 0.55 M. What is the rate constant for this reaction?

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Answer 1

For a second order reaction, t_1/2 = 1/k[A]_o

We know [A]o = 0.55 M and t_1/2 = 10.5 s, therefore from t_1/2 = 1/k[A]_o we can solve for k

10.5 s = 1/0.55 M x k

k = 1/(0.55 M)(10.5 s)

k = 0.173 M^-1s^-1