What is the pH of a solution made by dissolving the 37 g of KOH in 500 mL of water, with no buffer in it?
moles KOH = 37g/molar mass KOH.
moles OH- = moles KOH and M KOH = moles/L soln; therefore,
pOH = -log(OH^-) and convert to pH.
To find the pH of a solution, we need to calculate the concentration of hydroxide ions (OH-) in the solution, as pH is a measure of the concentration of hydrogen ions (H+).
First, we need to calculate the number of moles of KOH. The molar mass of potassium hydroxide (KOH) is 56.11 g/mol (39.10 g/mol for potassium + 16.00 g/mol for oxygen + 1.01 g/mol for hydrogen).
Number of moles of KOH = mass of KOH / molar mass of KOH
Number of moles of KOH = 37 g / 56.11 g/mol
Next, we need to calculate the molarity (moles per liter) of the KOH solution. Since we have 500 mL of water, we need to convert it to liters:
Volume of solution = 500 mL = 500/1000 L = 0.5 L
Molarity of KOH solution = number of moles of KOH / volume of solution
Now, we can calculate the hydroxide ion concentration (OH-) using the stoichiometry of the KOH dissociation reaction which is:
KOH → K+ + OH-
From the balanced equation, we can see that every mole of KOH produces one mole of hydroxide ions (OH-).
Therefore, the concentration of OH- in the solution is equal to the molarity of KOH.
Finally, we can use the concentration of OH- to calculate the pOH and then convert it to pH using the equation: pH = 14 - pOH.
So, to summarize the steps:
1. Calculate the number of moles of KOH.
2. Calculate the molarity of the KOH solution.
3. Calculate the concentration of OH-.
4. Calculate the pOH.
5. Calculate the pH using the equation pH = 14 - pOH.
Follow these steps with the given values and you will be able to determine the pH of the solution made by dissolving 37 g of KOH in 500 mL of water with no buffer in it.