Chapter 11, Problem 99QRT

(a)

Interpretation Introduction

Interpretation:

The half-life for the decomposition of $N_2{O}_5$ has to be calculated.

Concept Introduction:

The integrated rate equation for first order reaction is given below.

  $\lambda t=\ln \frac{{\left[A\right]}_o}{{\left[A\right]}_t}$

Where,

    $\lambda$ is the rate constant/ decay constant

    $t$ is the time taken to change the concentration from ${\left[A\right]}_{o}to{\left[A\right]}_t$

    ${\left[A\right]}_o$ is the initial concentration of $A$

    ${\left[A\right]}_t$ is the final concentration $A$

Half-life of a first order reaction can be calculated using following equation.

  $t_{\frac{1}{2}}=\frac{0.693}{\lambda }$

(b)

Interpretation Introduction

Interpretation:

The time taken for the concentration to drop to $\frac{1}{32}$ of its original value has to be calculated.

Concept Introduction:

Refer to part (a).

(c)

Interpretation Introduction

Interpretation:

The time taken for the concentration to drop from  $3.4\times {10}^{-3}mol/Lto2.3\times {10}^{-5}mol/L$ has to be calculated.

Concept Introduction:

Refer to part (a).