A solution of NaOH (aq) contains 8.2 grams of NaOH(s) per 100.0 mL of solution. Calcualte Ph and POH at 25 degrees celsiuis
Oh, chemistry questions always bring out my "base" instincts! Let's dive into it, shall we?
To calculate the pH and pOH of a solution, we first need to calculate the concentration of hydroxide ions, [OH-]. Given that the solution contains 8.2 grams of NaOH per 100.0 mL of solution, we can find the concentration using the molar mass of NaOH.
The molar mass of NaOH is 22.99 g/mol for Na + 16.00 g/mol for O + 1.01 g/mol for H = 39.99 g/mol.
Concentration of NaOH: 8.2 g / 39.99 g/mol = 0.205 mol.
Now, we need to find the concentration of hydroxide ions. Since NaOH is a strong base, it fully dissociates in water:
[OH-] = [NaOH]
So, the concentration of hydroxide ions is 0.205 mol/0.1 L = 2.05 mol/L.
Now, let's calculate pOH using the formula:
pOH = -log10[OH-]
pOH = -log10(2.05) ≈ -0.31
Finally, we can determine the pH using the equation:
pH + pOH = 14
pH = 14 - pOH
pH = 14 - (-0.31) ≈ 14.31
So, at 25 degrees Celsius, the pH of the solution is approximately 14.31 and the pOH is approximately -0.31.
To calculate the pH and pOH of a solution, we need to know the concentration of hydroxide ions ([OH-]) or the concentration of hydronium ions ([H3O+]).
Given that the solution contains 8.2 grams of NaOH per 100.0 mL of solution, we need to convert this to molarity (M).
Step 1: Convert grams to moles.
To convert grams to moles, we need to know the molar mass of NaOH.
The molar mass of NaOH = 22.99 g/mol (Na) + 16.00 g/mol (O) + 1.01 g/mol (H) = 39.99 g/mol.
Moles of NaOH = (mass of NaOH) / (molar mass of NaOH)
Moles of NaOH = (8.2 g) / (39.99 g/mol)
Moles of NaOH = 0.205 mol
Step 2: Convert volume to liters.
Given that we have 100.0 mL of solution, we need to convert it to liters.
Liters of solution = (volume of solution) / (1000 mL/L)
Liters of solution = (100.0 mL) / (1000 mL/L)
Liters of solution = 0.100 L
Step 3: Calculate the concentration (Molarity) of NaOH.
Molarity (M) = (moles of solute) / (liters of solution)
Molarity (M) = (0.205 mol) / (0.100 L)
Molarity (M) = 2.05 M
Now that we have the concentration of hydroxide ions ([OH-]), we can calculate the pOH and pH.
Step 4: Calculate the pOH.
pOH = -log10([OH-])
pOH = -log10(2.05)
pOH = 0.69
Step 5: Calculate the pH.
pH + pOH = 14 (at 25 degrees Celsius)
pH = 14 - pOH
pH = 14 - 0.69
pH = 13.31
Therefore, at 25 degrees Celsius, the pH of the solution is 13.31 and the pOH is 0.69.
To calculate the pH and pOH of a solution of NaOH at 25 degrees Celsius, you need to determine the concentration of hydroxide ions (OH-) in the solution.
Step 1: Convert grams of NaOH to moles
To do this, use the molar mass of NaOH, which is 40.00 g/mol.
8.2 grams of NaOH = (8.2 g) / (40.00 g/mol) = 0.205 moles of NaOH
Step 2: Convert mL of solution to liters
100.0 mL of solution = 100.0 mL * (1 L / 1000 mL) = 0.100 L
Step 3: Calculate concentration of OH- ions
The concentration of OH- ions can be found by dividing the moles of NaOH by the volume in liters.
Concentration of OH- ions = 0.205 moles / 0.100 L = 2.05 M
Step 4: Calculate pOH
pOH is calculated by taking the negative logarithm (base 10) of the concentration of hydroxide ions.
pOH = -log10(2.05) = 0.6874
Step 5: Calculate pH
The pH of a solution can be found using the equation: pH + pOH = 14
pH = 14 - pOH = 14 - 0.6874 = 13.3126
Therefore, at 25 degrees Celsius, the pH of the NaOH solution is approximately 13.31 and the pOH is approximately 0.69.
mols NaOH = grams/molar mass
M NaOH = mols/L solution
M OH^- = M NaOH
pOH = -log(OH^-)
pH + pOH = pKw = 14.