Question

The rate constant for this first‑order reaction is 0.740 s − 1 0.740 s−1 at 400 ∘ C. 400 ∘C. A ⟶ products A⟶products How long, in seconds, would it take for the concentration of A A to decrease from 0.790 M 0.790 M to 0.230 M? 0.230 M?

Answer 1

1.668 S

Explanation:

We are given that

`A\rightarrow`Product

For first order reaction,

`t=(1)/(k)ln(A_0)/(A)`

`t=(2.303)/(k)log(A_0)/(A)`

Rate constant=k=
`0.740s^(-1)`

Temperature=
`T=400^(\circ)`

We have to find the time taken by the reaction when concentration of A to decrease from 0.790 M to 0.230 M.

`A_0=0.79 M`

`A=0.230`

Substitute the values then we get

`t=(2.303)/(0.740)log(0.79)/(0.23)`

`t=1.668 s`

Hence, it would take 1.668 s for the concentration of A to decrease from 0.790 M to 0.230 M.