How many milliliters of a 15.0%, by mass solution of {KOH}(aq) (d = 1.14 g/mL) are required to produce 25.0 L of a solution with pH = 11.60?
Calculate molarity of KOH solution.
That is 1.14 g/mL x 1000 mL x 0.15 = approximately 175 grams KOH. So mols KOH = 175/56 = about 3 M.
Now go to what you want to prepare. You want pH = 11.60 which is pOH or 2.40 or (OH^-) = about 0.004 M.
Now mL(soln 1) x M(soln 1) = mL(soln 2) x M(soln 2)
You need to redo the whole problem because I estimated molar masses and rounded here and there to make it quicker to calculate. The answer is approximate only so you need to put in the exact values.
thanks alot !! =)
To determine how many milliliters of a 15.0% by mass solution of KOH (potassium hydroxide) are required to produce 25.0 L of a solution with a pH of 11.60, we need some additional information.
The pH of a solution provides information about its acidity or alkalinity. In this case, a pH of 11.60 indicates that the solution is alkaline.
However, the pH alone is not sufficient to determine the concentration of KOH in the solution. We need additional information such as the concentration or molarity of the KOH solution, or the amount of KOH in grams or moles.
Please provide more information or clarify the question so that I can assist you further.
To determine the number of milliliters of a 15.0% by mass solution of KOH(aq) required to produce a 25.0 L solution with a pH of 11.60, we need to follow a step-by-step approach.
Step 1: Determine the molar concentration of hydroxide ions (OH-) in the solution.
The pH of a solution is a measure of its hydrogen ion (H+) concentration. Since we know the pH is 11.60, we can determine the concentration of hydroxide ions (OH-) by calculating the pOH.
pOH = 14 - pH
pOH = 14 - 11.60
pOH = 2.40
Now, convert the pOH to the concentration of OH- ions:
[OH-] = 10^(-pOH)
[OH-] = 10^(-2.40)
[OH-] ≈ 0.004 × 0.004
[OH-] ≈ 0.00001 M
Step 2: Determine the molecular weight of KOH.
The molecular weight of KOH can be calculated by adding the atomic masses of potassium (K), oxygen (O), and hydrogen (H).
Molecular weight of KOH = (atomic mass of K) + (atomic mass of O) + (atomic mass of H)
Molecular weight of KOH = 39.10 g/mol + 16.00 g/mol + 1.01 g/mol
Molecular weight of KOH ≈ 56.11 g/mol
Step 3: Calculate the mass of KOH required to produce 25.0 L of the solution.
The concentration of the KOH solution is given as 15.0% by mass, meaning it contains 15.0 g of KOH per 100.0 g of solution.
Mass of KOH = (15.0 g / 100.0 g) × (mass of solution)
Mass of KOH = (15.0 / 100.0) × (25.0 L × 1.14 g/mL)
Mass of KOH ≈ 4.28 g
Step 4: Determine the volume of the 15.0% KOH solution required.
To find the volume of the 15.0% KOH solution required, we need to use the mass of KOH and the density of the solution.
Volume of KOH solution = (mass of KOH) / (density of KOH solution)
Volume of KOH solution = 4.28 g / 1.14 g/mL
Volume of KOH solution ≈ 3.75 mL
Therefore, approximately 3.75 milliliters of the 15.0% by mass solution of KOH(aq) are required to produce 25.0 L of the solution with a pH of 11.60.