Calculate the PH and POH of an aqueous solution that is 25.00% of HCL by mass and density of 1.35g/no
25% HCl means 25 g HCl in 100 g solution.
volume of 100 g solution is mass/density. Substitute and solve for volume in mL, convert to L.
Calculate mols HCl from grams HCl/molar mass HCl.
Then M HCl = mols HCl/L solution.
pH = -log(HCl)
pH + pOH = pKw = 14. You have pH and pKw, solve for pOH.
Post your work if you get stuck.
Results
To calculate the pH and pOH of an aqueous solution of HCl, we need to know the concentration of HCl in moles per liter (Molarity). However, you have provided the percentage by mass and the density of the solution, which cannot be directly used to determine the molarity.
To calculate the molarity (M) of HCl, we need to convert the mass percent to grams and then calculate the moles of HCl present. Here's how you can do it:
Step 1: Convert the percentage to grams:
If the solution is 25.00% HCl by mass, it means that 100g of the solution contains 25.00g of HCl and the remaining 75.00g is water.
Step 2: Calculate the moles of HCl:
To calculate the moles of HCl, we need to use the molar mass of HCl, which is the sum of the atomic masses of hydrogen (H) and chlorine (Cl). The molar mass of HCl is approximately 36.46 g/mol.
Moles of HCl = Mass of HCl (in grams) / Molar mass of HCl
Step 3: Calculate the volume of the solution in liters:
To calculate the volume of the solution, we need to use the given density. The density of the solution is 1.35 g/mL (or 1.35 g/cm³) which is the same as 1350 g/L.
Volume of solution (in liters) = Mass of solution (in grams) / Density of solution
Now that we have determined the moles of HCl and the volume of the solution in liters, we can calculate the molarity (M) of the HCl solution:
Molarity (M) = Moles of HCl / Volume of solution (in liters)
Once we have the molarity (M) of HCl, we can calculate the pH and pOH using the following formulas:
pH = -log[H+]
pOH = -log[OH-]
pH + pOH = 14 (at 25°C)
Since HCl completely dissociates in water, there will be no OH- ions present in the solution. Hence, the pOH will be 0.
Now, using the calculated molarity, we can find the pH using the formula pH = -log[H+].