Calculate the pH and pOH of a hydrochloric acid solution prepared by dissolving 30.50-kg of hydrogen chloride gas in 806-L of water at SATP.
I would convert 30.50 kg to grams.
mols HCl = grams/molar mass
Then M = mols/L
Since HCl is 100% ionized, (H^+) = (HCl) and pH = -log(H^+)
Then pH + pOH = pKw = 14. Use this to calculate pOH.
Finally, pOH = -log(OH^-) and calculate OH^-.
To calculate the pH and pOH of a hydrochloric acid solution, we need to know the concentration of the acid in moles per liter (M). Given the mass of hydrogen chloride gas and the volume of water, we can determine the concentration of the hydrochloric acid solution.
1. Calculate the number of moles of hydrogen chloride gas:
Given the molar mass of hydrogen chloride (HCl) is 36.5 g/mol, we can convert the mass of hydrogen chloride gas to moles:
Moles of HCl = mass of HCl gas / molar mass of HCl
= 30.50 kg / 36.5 g/mol
= 30,500 g / 36.5 g/mol
= 836.99 mol
2. Calculate the concentration in moles per liter (M):
Since we are dissolving the hydrogen chloride gas in 806 L of water, we can calculate the concentration:
Concentration (M) = moles of solute / volume of solution (in liters)
= 836.99 mol / 806 L
= 1.037 M
With the concentration of the hydrochloric acid solution (1.037 M), we can now calculate the pH and pOH using the formulas below:
pH = -log[H+]
pOH = -log[OH-]
pH + pOH = 14 (at 25°C and 1 atm)
3. Calculate the pH:
The concentration of hydrogen ions ([H+]) in a hydrochloric acid solution is the same as the concentration of the acid itself. Therefore, the pH can be calculated as:
pH = -log(1.037)
4. Calculate the pOH:
The pOH is calculated using the equation:
pOH = 14 - pH
Now, using the calculated values in steps 3 and 4, we can determine the pH and pOH of the hydrochloric acid solution.