2.) A particular vinegar is found to contain 5.9% acetic acid by mass.
What mass of this vinegar should be diluted with water to produce 0.750 L of a solution with pH = 4.58?
To solve this problem, we need to determine the amount of vinegar required to produce a 0.750 L solution with a pH of 4.58.
Step 1: Understand the problem
We are given that the vinegar contains 5.9% acetic acid by mass. This information will help us calculate the amount of acetic acid present in a given mass of vinegar. We also know that we want to dilute this vinegar with water to produce a 0.750 L solution with a pH of 4.58.
Step 2: Find the concentration of acetic acid
To determine the concentration of acetic acid in the vinegar, we convert the percentage to a decimal by dividing it by 100. In this case, 5.9% becomes 0.059. This means that for every 100 grams of vinegar, there are 0.059 grams of acetic acid.
Step 3: Calculate the amount of acetic acid needed
We can calculate the amount of acetic acid needed to produce a 0.750 L solution with a pH of 4.58. The pH value indicates the concentration of H+ ions in a solution. In this case, a pH of 4.58 corresponds to a concentration of 10^(-4.58) mol/L of H+ ions. Since acetic acid is a weak acid, it only partially dissociates in water, producing H+ ions.
Step 4: Calculate the amount of vinegar needed
The concentration of acetic acid in vinegar is given in terms of mass percentage. To calculate the mass of acetic acid needed, we need to determine the mass of vinegar required.
Step 5: Final calculation
To find the mass of vinegar needed, we use the formula:
Mass of vinegar = (Mass of acetic acid needed) / (Concentration of acetic acid in vinegar)
Using the information from steps 3 and 4, we can substitute the values into the formula to calculate the mass of vinegar.