Calculate the concentrations of hydronium and hydroxide ions in a solution prepared by dissolving 0.345g of solid NaOH in enough water to make 225mL of solution. Also calculate the pH and pOH of the solution.
NaOH is a strong electrolyte. It ionizes completely.
moles = grams/molar mass.
Solve for moles.
M = moles/L soln.
Substitute and solve for OH, convert to pOH, then to pH.
Thank you! I will probably have more questions in a bit! I appreciate it!
To calculate the concentrations of hydronium (H3O+) and hydroxide (OH-) ions, as well as the pH and pOH of the solution, we need to follow several steps. Let's break it down:
Step 1: Determine the number of moles of NaOH.
First, we need to convert the mass of NaOH to moles.
The molar mass of NaOH is:
Na = 22.99 g/mol
O = 16.00 g/mol
H = 1.01 g/mol
The molar mass of NaOH is:
Na = 22.99 g/mol
O = 16.00 g/mol
H = 1.01 g/mol
So, the molar mass of NaOH is:
22.99 g/mol + 16.00 g/mol + 1.01 g/mol = 40.00 g/mol
To convert grams to moles, we use the formula:
moles = mass / molar mass
Plugging in the values:
moles of NaOH = 0.345 g / 40.00 g/mol
Step 2: Calculate the volume of the solution in liters.
The given volume of the solution is 225mL. To calculate the volume in liters, we divide by 1000:
volume = 225 mL / 1000 mL/L
Step 3: Determine the molarity of the NaOH solution.
Molarity (M) is defined as moles of solute per liter of solution. We can calculate it using the formula:
molarity (M) = moles of solute / volume of solution (in liters)
Plugging in the values:
molarity (M) = moles of NaOH / volume of solution (in liters)
Step 4: Determine the concentrations of hydronium and hydroxide ions.
Since NaOH is a strong base, it completely dissociates in water to form one hydroxide ion (OH-) and one sodium ion (Na+).
This means the concentration of OH- is the same as the molarity of NaOH.
Concentration of OH- (hydroxide ions) = molarity of NaOH
Since water is neutral, the concentration of H3O+ (hydronium ions) is equal to OH- concentration.
Concentration of H3O+ (hydronium ions) = concentration of OH- (hydroxide ions)
Step 5: Calculate the pH and pOH.
The pH is a measure of the acidity or basicity of a solution and is calculated using the formula:
pH = -log[H3O+]
The pOH is calculated using:
pOH = -log[OH-]
Since [H3O+] = [OH-] (due to water being neutral), the pH and pOH are equal.
Using the values we calculated, you can find the pH and pOH of the solution.
It's important to note that the pH and pOH scale ranges from 0 to 14, where a pH of 7 is considered neutral, below 7 is acidic, and above 7 is basic.