What is the pH of a 0.36% by mass HCl?(density=1.0 g/mL)
First calculate M.
1000 mL x 1.0 g/mL x 0.36 x (1/molar mass HCl) = ? M.
Then convert M to pH using pH = -log(H^+).
To find the pH of a solution, we need to know the concentration of hydrogen ions (H+) in the solution. In this case, we have a 0.36% by mass HCl solution.
Step 1: Calculate the molarity (M) of the HCl solution.
To do this, we need to convert the mass percentage to grams.
Mass of HCl = 0.36% * mass of solution
Mass of solution = density * volume
Given density = 1.0 g/mL, we assume volume = 100 mL for convenience.
Mass of HCl = 0.36% * (1.0 g/mL * 100 mL)
= 0.36 g
The molar mass of HCl is approximately 36.46 g/mol.
Molarity (M) = moles of solute / volume of solution (in L)
= mass of HCl (in g) / (molar mass of HCl * volume of solution(in L))
= 0.36 g / (36.46 g/mol * 0.100 L)
= 0.987 M
Step 2: Calculate the concentration of H+ ions (in mol/L).
Since HCl is a strong acid, it dissociates completely, yielding one H+ ion for every HCl molecule.
Therefore, the concentration of H+ ions in the solution is the same as the molarity of the HCl solution.
Concentration of H+ ions = 0.987 M
Step 3: Calculate the H+ ion concentration as a decimal.
The pH is defined as the negative logarithm base 10 of the hydrogen ion concentration, so we need to convert the concentration to a decimal.
[H+] (in mol/L) = 0.987
Step 4: Calculate the pH.
pH = -log[H+]
= -log(0.987)
≈ 0.006
Therefore, the pH of the 0.36% by mass HCl solution is approximately 0.006.
To find the pH of a solution, we need to know the concentration of H+ ions in the solution. In this case, we can start by finding the molarity of the HCl solution.
First, we need to determine the mass of HCl in the solution. We are given that the solution is 0.36% by mass. This means that in 100 grams of the solution, there are 0.36 grams of HCl.
Next, we need to convert the mass of HCl to moles. To do this, we need the molar mass of HCl. The molar mass of hydrogen (H) is approximately 1 g/mol, and the molar mass of chlorine (Cl) is approximately 35.5 g/mol. Therefore, the molar mass of HCl is approximately 36.5 g/mol.
Now, we can calculate the number of moles of HCl in the solution using the following equation:
moles of HCl = mass of HCl / molar mass of HCl
moles of HCl = 0.36 g / 36.5 g/mol
moles of HCl ≈ 0.00986 mol
The solution has a density of 1.0 g/mL, which means that 100 grams of the solution is equal to 100 mL.
Next, we can find the molarity of the HCl solution using the equation:
molarity = moles of solute / volume of solution (in liters)
molarity = 0.00986 mol / 0.1 L
molarity = 0.0986 M
Now that we know the molarity of the HCl solution, we can calculate the concentration of H+ ions. Since HCl is a strong acid, it dissociates completely in water, so the concentration of H+ ions is the same as the molarity of the HCl solution.
Concentration of H+ ions = 0.0986 M
The pH of a solution can be calculated using the equation:
pH = -log[H+]
pH = -log(0.0986)
pH ≈ 1.01
Therefore, the pH of the 0.36% by mass HCl solution is approximately 1.01.