Chapter 6, Problem 6C.3ST

Interpretation Introduction

Interpretation:

How long is required for the concentration of substrate to fall from $1.28mmold{m}^{-3}$ to $0.040mmold{m}^{-3}$ have to be determined.

Concept Introduction:

Order of a reaction:  The sum of exponents of the concentrations in the rate law for the reaction is said to be order of a reaction.

  $\text{Order}\text{= }\text{x+y}$

Half-life is the time required for one half of a reactant to react.

For first order reaction $-kt=\ln \left(\frac{\left[A\right]}{\left[A_0\right]}\right)$

$\left[A\right]$ is the concentration of reactant A at time t ${\left[A\right]}_0$ is the  initial concentration of reactant, k is the rate constant.

Half-life period:

Half-life is defined as the time taken for amount of the sample to reduce to half of its starting value.  The symbol is ${\text{t}}_{\raisebox{1ex}{$\text{1}$}\!\left/ \!\raisebox{-1ex}{$\text{2}$}\right.}$.

  $t_{\frac{1}{2}}=\frac{\ln \left(2\right)}{k}$

Half-life for a first order reaction is, $t_{\frac{1}{2}}=\frac{0.693}{k}$