what is the pH and pOH of a solution made by adding water to 15 grams of HCl until the volume of the solution is 2500mL?
mols HCl = grams/molar mass
Then M HCl =mols HCl/L HCl
M HCl = M (H^+)
Then pH = -log(H^+)
and pH + pOH = pKw = 14. You know pH and pKw, convert to pOH.
To find the pH and pOH of the solution made by adding water to 15 grams of HCl, we need to calculate the concentration of HCl first.
Step 1: Calculate the number of moles of HCl:
The molar mass of HCl is approximately 36.46 g/mol.
Number of moles = mass / molar mass = 15 g / 36.46 g/mol = 0.411 mol
Step 2: Calculate the concentration of HCl:
Concentration (in mol/L) = moles / volume (in L) = 0.411 mol / 2.5 L = 0.1644 mol/L
Step 3: Calculate the pH:
pH is calculated using the formula: pH = -log[H+]
[H+] is the concentration of H+ ions in the solution.
Since HCl dissociates completely in water, the concentration of H+ ions is the same as the concentration of HCl.
[H+] = 0.1644 mol/L
pH = -log(0.1644) ≈ 0.784
Step 4: Calculate the pOH:
pOH is calculated using the formula: pOH = -log[OH-]
Since the solution is made by adding water to HCl, there are no OH- ions present in the solution. Hence, the pOH is 0.
Therefore, the pH of the solution is approximately 0.784 and the pOH is 0.
To find the pH and pOH of a solution made by adding water to 15 grams of HCl until the volume of the solution is 2500 mL, you need to determine the concentration of HCl in the solution. Once the concentration is known, you can use the equation -log[H+] to find the pH and pOH.
To begin, convert the mass of HCl to moles using its molar mass. The molar mass of HCl is approximately 36.46 g/mol.
moles of HCl = mass of HCl / molar mass of HCl
= 15 g / 36.46 g/mol
≈ 0.4116 mol
Next, calculate the concentration of HCl in the solution using the formula:
concentration (in mol/L) = moles of solute / volume of solution (in L)
Since the volume of the solution is given in mL, you need to convert it to L:
volume of solution = 2500 mL / 1000 mL/L
= 2.5 L
Now, calculate the concentration:
concentration = 0.4116 mol / 2.5 L
≈ 0.1646 mol/L
The concentration of HCl in the solution is approximately 0.1646 mol/L.
Now, you can find the pH and pOH. Since HCl is a strong acid, it completely dissociates in water, resulting in one mole of H+ ions per mole of HCl. Therefore, the concentration of H+ ions in the solution is also 0.1646 mol/L.
The pH is calculated using the equation:
pH = -log[H+]
pH = -log(0.1646)
pH ≈ 0.784
Similarly, the pOH is calculated using the equation:
pOH = -log[OH-]
Since HCl is a strong acid and completely dissociates, there will be no OH- ions present in the solution. Therefore, the pOH is 0.
Therefore, the pH of the solution is approximately 0.784, and the pOH is 0.