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The rate constant for a second-order reaction is 0.54 m-1s-1. what is the half-life of this reaction if the initial concentration is 0.30 m?

Respuesta :

The correct answer is: 6.173 seconds.

Explanation:

The formula for half life (of reaction) is:

Half-life = [tex]\frac{1}{K*I}[/tex] --- (A)

Where,

K = Rate constant = 0.54 [tex]\frac{1}{ms}[/tex]

I = Initial concentration = 0.30 m


Plug in the values in equation (A):

Half-life = [tex]\frac{1}{0.54*0.30} = 6.173[/tex]

Hence, the half life is 6.173 seconds.

The half-life of a second-order reaction is [tex]\boxed{{\text{6}}{\text{.173 seconds}}}[/tex]  

Further explanation:

Second-order reaction:

A reaction is said to be of second-order if its rate is proportional to the square of the concentration of one reactant. The general example of second-order reaction is,

[tex]2{\text{A}}\to{\text{P}}[/tex]

Here,

A is the reactant.

P is the product.

The rate is calculated by using the following equation:

[tex]{\text{Rate}}={\text{k}}{\left[{\text{A}}\right]^2}[/tex]

Another form of second-order reaction is as follows:

[tex]{\text{A}}+{\text{B}}\to{\text{P}}[/tex]

Here,

A and B are the two different reactants.

P is the product.

The rate is calculated by using the following equation:

[tex]{\text{Rate}}={\text{k}}\left[{\text{A}}\right]\left[{\text{B}}\right][/tex]

Half-life:

Half-life is defined as the time required to reduce the concentration of reactant to half of its initial value. It is denoted by [tex]{{\text{t}}_{1/2}}[/tex] . The general expression to calculate [tex]{{\text{t}}_{1/2}}[/tex]  of second-order reaction is,

[tex]{{\text{t}}_{1/2}}=\frac{1}{{{\text{k}}{{\left[{\text{A}}\right]}_{\text{0}}}}}[/tex]                                                              …… (1)

Here,

[tex]{{\text{t}}_{1/2}}[/tex]  is the half-life of the reaction.

k is the rate constant for the reaction.

[tex]{\left[ {\text{A}}\right]_{\text{0}}}[/tex]  is the initial concentration of the reactant.

The rate constant for the given reaction is [tex]0.54\;{{\text{M}}^{-1}}{{\text{s}}^{-1}}[/tex] .

The initial concentration of the given reaction is 0.30 M.

Substitute these values in equation (1).

[tex]\begin{aligned}{{\text{t}}_{1/2}}&=\frac{1}{{\left({0.54\;{{\text{M}}^{ - 1}}{{\text{s}}^{ - 1}}}\right)\left( {{\text{0}}{\text{.30 M}}}\right)}}\\&=\frac{1}{{0.162\;{{\text{s}}^{ - 1}}}}\\&=6.1728\;{\text{s}}\\&\approx 6.173\;{\text{s}}\\\end{aligned}[/tex]

So, the half-life of a second-order reaction is 6.173 seconds.

Learn more:

1. Calculate the moles of chlorine in 8 moles of carbon tetrachloride: https://brainly.com/question/3064603

2. Calculate the moles of ions in the solution: https://brainly.com/question/5950133

Answer details:

Grade: Senior School

Subject: Chemistry

Chapter: Chemical Kinetics

Keywords: second-order reaction, half-life, initial, half, 6.173 seconds, 0.30 m, k, A0, A, B, P, 2A, reactant, product, t1/2.