How much of NaOH (in grams) is needed to prepare 546 mL of solution with a pH of 10.00 ?
To determine the amount of NaOH needed to prepare a solution with a pH of 10.00, we need additional information. The pH of a solution does not solely depend on the amount of solute, but also on the concentration.
Please provide the concentration of NaOH (in Molarity) that is required for the solution, and I can guide you through the calculation.
To determine the amount of NaOH (sodium hydroxide) needed to prepare a solution with a pH of 10.00, we need to consider the dissociation of NaOH in water, which will result in the release of hydroxide ions (OH-).
Step 1: Calculate the concentration of hydroxide ions
Since the pH is a measure of the concentration of hydrogen ions (H+), we can use the equation:
pH = -log[H+]
To obtain the concentration of hydroxide ions (OH-), we use the fact that water is neutral, so the concentration of H+ ions is equal to the concentration of OH- ions:
[H+] = [OH-]
Therefore, we can calculate the concentration of OH- ions using the equation:
pOH = -log[OH-]
Given that the pH is 10.00, we can find the pOH by subtracting 10.00 from 14 (pOH + pH = 14):
pOH = 14 - 10.00 = 4
Now, we convert the pOH back to the concentration of OH- ions using the equation:
[OH-] = 10^(-pOH)
[OH-] = 10^(-4)
[OH-] = 0.0001 M
Step 2: Calculate the number of moles of hydroxide ions
To determine the number of moles of hydroxide ions, we multiply the concentration (in moles per liter) by the volume (in liters) of the solution. However, the volume is given in milliliters, so we need to convert it to liters:
546 mL = 546/1000 = 0.546 L
Now, we can calculate the number of moles of hydroxide ions:
moles of OH- = concentration × volume
moles of OH- = 0.0001 M × 0.546 L
Step 3: Calculate the molar mass of NaOH
To find the mass of NaOH required, we need to know the molar mass of NaOH, which is the sum of the atomic masses of sodium (Na), oxygen (O), and hydrogen (H):
Molar mass of NaOH = atomic mass of Na + atomic mass of O + atomic mass of H
Molar mass of NaOH = 22.99 g/mol + 16.00 g/mol + 1.01 g/mol
Molar mass of NaOH = 39.00 g/mol
Step 4: Calculate the mass of NaOH
Finally, to find the mass of NaOH required, we multiply the number of moles of hydroxide ions by the molar mass of NaOH:
mass of NaOH = moles of OH- × molar mass of NaOH
mass of NaOH = moles of OH- × 39.00 g/mol
Substituting the calculated value for moles of OH-:
mass of NaOH = 0.0001 M × 0.546 L × 39.00 g/mol
mass of NaOH = 0.001764 g
Therefore, approximately 0.0018 grams of NaOH are needed to prepare a 546 mL solution with a pH of 10.00.
I agree.
The answer I got is
2.18 X 10^-3 g of NaOH