What is the of a solution obtained by dissolving two extra-strength aspirin tablets, containing 594 of acetylsalicylic acid each, in 202 of water?
The active ingredient in aspirin is acetylsalicylic acid , a monoprotic acid with Ka=3.3*10^-4 at 25 C.
Can you provide the method, for some reason I keep getting the answer wrong.
oh no
If anyone has the answer to this add me on snap msully726
Sure! To find the pH of a solution obtained by dissolving two extra-strength aspirin tablets in water, you need to calculate the concentration of acetylsalicylic acid (ASA) in the solution and then use the acid dissociation constant (Ka) to find the pH.
We can start by calculating the moles of ASA present in the solution. Each tablet contains 594 mg of ASA, so two tablets would have a total of 594 mg * 2 = 1188 mg of ASA.
To convert milligrams of ASA to moles, we need to divide by the molar mass of ASA. The molar mass of ASA is 180.16 g/mol, which is equal to 180.16 mg/mmol. Therefore, the moles of ASA in the solution can be calculated as follows:
Moles of ASA = (1188 mg) / (180.16 mg/mmol) = 6.597 mmol
Next, we need to calculate the volume of the solution. The problem states that the tablets were dissolved in 202 mL of water. Therefore, the volume of the solution is 202 mL.
Now we can calculate the concentration of ASA in the solution by dividing the moles of ASA by the volume of the solution:
Concentration of ASA = (6.597 mmol) / (202 mL) = 0.0326 mol/L
Now that we have the concentration of ASA, we can use the acid dissociation constant (Ka) to find the pH. The Ka is given as 3.3 * 10^-4.
The equation for the dissociation of ASA in water is as follows:
ASA (aq) ⇌ H+ (aq) + A- (aq)
Since ASA is a monoprotic acid, it will ionize to release one H+ ion per molecule. Therefore, the concentration of H+ ions equals the concentration of ASA.
[H+] = 0.0326 mol/L
Now, we can use the formula for pH to calculate the pH:
pH = -log[H+]
pH = -log(0.0326)
Using a calculator, the pH comes out to be approximately 1.49.
So, the pH of the solution obtained by dissolving two extra-strength aspirin tablets in water is approximately 1.49.