to clean a clogged drain, 26 g of sodium hydroxide is added to water to make 150 ml of solution what are the pH and pOH values for the solution?
To determine the pH and pOH values of a solution prepared by adding 26 g of sodium hydroxide (NaOH) to water to make 150 ml of solution, we first need to calculate the concentration of NaOH in the solution. From there, we can use that concentration to find the pH and pOH values.
Here's how you can calculate it:
1. Determine the molar mass of NaOH:
- Molar mass of Na = 22.99 g/mol
- Molar mass of O = 16.00 g/mol
- Molar mass of H = 1.01 g/mol
- Molar mass of NaOH = (22.99 g/mol) + (16.00 g/mol) + (1.01 g/mol) = 39.00 g/mol
2. Calculate the number of moles of NaOH:
- Moles = mass / molar mass
- Moles = 26 g / 39.00 g/mol ≈ 0.67 mol
3. Determine the concentration of NaOH:
- Concentration (in moles per liter) = moles / volume (in liters)
- Volume = 150 ml = 150/1000 = 0.15 L
- Concentration = 0.67 mol / 0.15 L ≈ 4.47 mol/L
4. Calculate the pOH:
- pOH = -log10[OH-]
- Since NaOH is a strong base that fully dissociates, the concentration of hydroxide ions (OH-) is equal to the concentration of NaOH.
- Therefore, pOH = -log10(4.47) ≈ 0.35
5. Calculate the pH:
- Since pH + pOH = 14 (at 25°C), we can now calculate the pH:
- pH = 14 - pOH = 14 - 0.35 ≈ 13.65
Therefore, the pH value of the solution is approximately 13.65, and the pOH value is approximately 0.35.
It is worth mentioning that a solution with a pH of 13.65 is highly alkaline, which is typical for a solution containing sodium hydroxide. When working with such strong bases, it is crucial to take appropriate safety precautions and use protective equipment.
To calculate the pH and pOH values for the solution, we first need to determine the concentration of the sodium hydroxide solution.
Step 1: Convert the mass of sodium hydroxide to moles.
The molar mass of sodium hydroxide (NaOH) is 22.99 g/mol + 16.00 g/mol + 1.008 g/mol = 39.997 g/mol.
So, moles of NaOH = mass of NaOH / molar mass of NaOH = 26 g / 39.997 g/mol = 0.65 mol.
Step 2: Convert the volume of the solution to liters.
The volume of the solution is 150 mL, which is equivalent to 150/1000 = 0.15 L.
Step 3: Calculate the concentration of NaOH.
Concentration (molarity) = moles / volume = 0.65 mol / 0.15 L = 4.33 mol/L.
Step 4: Calculate the pOH.
pOH = -log[OH-].
Since sodium hydroxide is a strong base and dissociates completely in water, the concentration of hydroxide ions ([OH-]) is equal to the concentration of NaOH.
Therefore, pOH = -log(4.33) ≈ 0.36.
Step 5: Calculate the pH using the equation: pH + pOH = 14.
pH + 0.36 = 14.
pH = 14 - 0.36 = 13.64.
So, the pH value for the solution is approximately 13.64, and the pOH value is approximately 0.36.
molarity = moles/L
moles = g/molar mass
So 25 g NaOH is how many moles?
You place that in 150 mL water (0.150L) and the molarity is what?
Then (NaOH) = OH^-. Convert that to pOH, then to pH.