What is the pH of a solution if two aspirin each containing 500mg of acetylsalicyclic acid were dissolved in 325 ml of water?

Question

What is the pH of a solution if two aspirin each containing 500mg of acetylsalicyclic acid were dissolved in 325 ml of water?

Answer 1

If we call aspirin, HA, then the acid dissociates in water as

HA ==> H^+ + A^-

Ka = (H^+)(A^-)/(HA)
(H^+) = x
(A^-) = x
(HA) = moles aspirin/L soln.
moles aspirin = 2*500/molar mass aspirin.
L soln = 0.325 L
Solve for x and convert to pH.
Post your work if you get stuck.

Answer 2

To determine the pH of a solution, we need to first understand that pH is a measure of the acidity or basicity of a solution. It is determined by the concentration of hydrogen ions (H+) in the solution.

In this case, we have two aspirin tablets, each containing 500mg of acetylsalicyclic acid, dissolved in 325ml of water. Acetylsalicylic acid is a weak acid, and when it dissolves in water, it partially dissociates into ions.

To find the pH, we need to calculate the concentration of H+ in the solution. To do this, we can use the dissociation constant (Ka) of acetylsalicylic acid. The dissociation constant is a measure of how much acetylsalicylic acid dissociates in water.

However, the dissociation constant for acetylsalicylic acid is not readily available. Therefore, to simplify our calculation, we'll assume that acetylsalicylic acid fully dissociates into H+ and its corresponding conjugate base (in this case, acetylsalicylate ion).

First, let's convert the mass of acetylsalicylic acid to moles:
- Molecular weight of acetylsalicylic acid = 180.15 g/mol
- Mass of acetylsalicylic acid = 2 tablets × 500 mg = 1000 mg = 1 g
- Moles of acetylsalicylic acid = 1 g ÷ 180.15 g/mol = 0.00555 mol

Next, let's calculate the concentration of acetylsalicylic acid in the solution:
- Volume of water = 325 ml = 0.325 L
- Concentration of acetylsalicylic acid = 0.00555 mol ÷ 0.325 L = 0.0171 M

Since we assumed that the acetylsalicylic acid fully dissociates, the concentration of H+ will also be 0.0171 M.

Finally, we can calculate the pH using the equation:
pH = -log[H+]

- pH = -log(0.0171)
- pH ≈ 1.77

So, the pH of the solution is approximately 1.77.

What is the pH of a solution if two aspirin each containing 500mg of acetylsalicyclic acid were dissolved in 325 ml of water?

If we call aspirin, HA, then the acid dissociates in water as

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To determine the pH of a solution, we need to first understand that pH is a measure of the acidity or basicity of a solution. It is determined by the concentration of hydrogen ions (H+) in the solution.