Chapter 16, Problem 16.95SP

Acetic acid ${\text{(CH}}_{\text{3}}{\text{COOH; K}}_{\text{a}}\text{ = 1}\text{.8}\times {\text{10}}^{\text{-5}})$ has a concentration in vinegar of $3.50\%$ by mass. What is the pH of vinegar? (The density of vinegar is 1.02 g/mL.)