A typical aspirin tablet contains 325 mg of acetylsalicylic acid (HC9H7O4). Calculate the pH of a solution that is prepared by dissolving two aspirin tablets in one cup (237 mL) of solution. Assume the aspirin tablets are pure acetylsalicylic acid, Ka=3.3×10−4.

pH =2.685

Explanation:

mass of acetylsalicylic acid, m = 2  ×  325 m g  ×  (1 g   / 1000 m g )

=  0.65 g

Volume V = 237mL

dissociation constant, Ka =3.3×10⁻⁴

molecular weight of acetylsalicylic acid = 180.1 g/mol

mass of acetylsalicylic acid, (HC₉H₇O₄)

= 0.65 / 180.1

= 0.0036mol

concentration of HC₉H₇O₄ in a 237 mL solution

M = 0.0036 / 237ML

= 0.015M

in a 237 mL solution  HC₉H₇O₄ in water is

C₉H₇O₄⁻ ⇄ H⁺

Next, we show the changes in different phases that occur during the dissociation process. We use the value x as the concentration loss/gained during the dissociation process,

              HC₉H₇O₄          C₉H₇O₄⁻             H⁺

Initial          0.015               0                       0

change       -x                     x                       x

equilibrium  0.015 -x          x                      x

The equation for the dissociation constant Ka ,

using quadratic equation

x² + 3.3 * 10⁻⁴x - 4.95 * 10 ⁻⁶ = 0

x = 0.002066M

pH = -log[H⁺]

pH = -log[0.002066]

= 2.685

they are made of gases.

they have a spherical shape.

they make energy through fusion.

i think it is true since you can test the answer and can use observations to complete it.