Chapter 13, Problem 69E

(a)

Interpretation Introduction

Interpretation: The categorization of the given substance as an acid or a base and as an electrolyte or non- electrolyte.

Concept introduction: The $\text{pH}$ -scale is used to identify the acidic or basic nature of given substance.
Compound that accepts a proton is a base.
Compound that donates a proton is an acid.
An electrolyte is the substance which dissolves in water to produce ions.

(b)

Interpretation Introduction

Interpretation: The initial concentration of Ritalin in the human’s bloodstream.

Concept introduction: The number of moles is defined as the ratio of given mass in grams to the molar mass.
  $\text{Mol}=\frac{\text{Mass}\text{of}\text{the}\text{given}\text{compound}}{\text{Molar}\text{mass}\text{of}\text{the}\text{compound}}$

Molarity (M) is the ratio of number of moles of solute to the volume of the solution in liters.

  $M=\frac{\text{Number}\text{of}\text{mole}\text{of}\text{Ritalin}}{\text{Volume}\text{of}\text{the}\text{solution}}$

(c)

Interpretation Introduction

Interpretation: The concentration of the given compound after six hour in the bloodstream.

Concept introduction: The half life of the given compound is calculated by the formula:
${\text{t}}_{\frac{1}{2}}=\frac{0.693}{k}$

Form above formula we can calculate the value of decay constant (k). After that following formula is used for find the concentration:
  $\begin{array}{c}\text{t}=\frac{2.303}{k}\log \frac{\text{Initial}\text{concentration}}{\text{Final}\text{concentration}}\\ \text{Final}\text{concentration}=\frac{e^{\frac{kt}{2.303}}}{\text{Initial}\text{concentration}}\end{array}$