Calculate the pH in a 0.00500 solution of NaOH.
NaOH is a strong base meaning that it ionized 100%. Therefore, 0.00500 M NaOH will give you 0.00500 M OH^-. Convert that to pOH, then to pH.
To calculate the pH of a solution of sodium hydroxide (NaOH), we need to first determine the concentration of hydroxide ions (OH-) in the solution.
NaOH is a strong base that dissociates completely in water, so we can assume that it will provide the same number of moles of hydroxide ions as the number of moles of NaOH added to the solution.
The molar mass of NaOH is:
Sodium (Na) = 22.99 g/mol
Oxygen (O) = 16.00 g/mol
Hydrogen (H) = 1.01 g/mol
So, the molar mass of NaOH is:
22.99 + 16.00 + 1.01 = 39.00 g/mol
We are given the concentration of NaOH as 0.00500M, which means there are 0.00500 moles of NaOH per liter of solution.
Since NaOH dissociates into one mole of Na+ and one mole of OH-, the concentration of OH- is also 0.00500M.
To calculate the pOH, we use the formula:
pOH = -log[OH-]
Using the concentration of OH-:
pOH = -log(0.00500)
Calculating pOH:
pOH = -(-2.30)
pOH = 2.30
Finally, to calculate the pH, we subtract the pOH from 14 (since pH + pOH = 14):
pH = 14 - pOH
pH = 14 - 2.30
pH ≈ 11.70
Therefore, the pH in a 0.00500M solution of NaOH is approximately 11.70.
To calculate the pH of a solution of NaOH, we need to determine the concentration of the hydroxide ions (OH-) in the solution.
Step 1: Start with the concentration of NaOH
The given concentration of NaOH is 0.00500 M (moles per liter).
Step 2: Determine the concentration of OH- ions
NaOH is a strong base that completely dissociates in water, yielding one hydroxide ion for every one sodium ion. Therefore, the concentration of OH- ions is equal to the concentration of NaOH.
Step 3: Calculate the pOH
pOH is the negative logarithm (base 10) of the hydroxide ion concentration: pOH = -log[OH-]. In this case, because the concentration of OH- ions is the same as NaOH, we can calculate pOH as pOH = -log(0.00500).
Step 4: Calculate the pH
The pH is the negative logarithm (base 10) of the hydrogen ion concentration (H+). Since pH + pOH = 14 (at 25°C), we can find the pH by subtracting the pOH from 14: pH = 14 - pOH.
Solving this mathematically, we get:
pOH = -log(0.00500)
pOH ≈ 2.30 (rounded to two decimal places)
pH = 14 - 2.30
pH ≈ 11.70 (rounded to two decimal places)
Therefore, the pH of the 0.00500 M NaOH solution is approximately 11.70.