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The reaction A - gt Products follows pseudo-fir... - SS2 Chemistry Chemical Kinetics Question

The reaction A -> Products follows pseudo-first-order kinetics with respect to A. In a certain experiment, the concentration of A is 0.1 M, and the observed rate constant is 0.05 s-1. If the half-life of the reaction is 20 seconds, what will be the initial concentration of A in another experiment, where the half-life is 10 seconds?

Given: [A]₁ = 0.1 M, k₁ = 0.05 s-1, t₁/2 = 20 seconds. We need to find [A]₂.

For a pseudo-first-order reaction, the half-life (t₁/2) is given by:

t₁/2 = ln(2) / k

where k is the rate constant.

Now, let's find the rate constant (k₂) for the second experiment where t₁/2 = 10 seconds:

k₂ = ln(2) / t₁/2

k₂ = ln(2) / 10 s

k₂ ≈ 0.0693 s^-1

Now, using the pseudo-first-order rate law, we can find [A]₂:

[A]₂ = k₂ x t₁/2

[A]₂ = 0.0693 s-1 x 10 s

[A]₂ ≈ 0.693 M

So, the initial concentration of A in the second experiment will be approximately 0.693 M.

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