How is the molarity of a 35% HCL calculated
https://socratic.org/questions/the-percentage-purity-of-commercial-hcl-is-35-w-w-the-specific-gravity-of-the-so
The molarity of a solution is calculated using the formula:
Molarity (M) = (moles of solute) / (volume of solution in liters)
To calculate the molarity of a 35% HCl (hydrochloric acid) solution, we need to know the density of the solution. The density of the solution will help us convert the percentage concentration into grams per milliliter (g/mL) or grams per liter (g/L).
1. Determine the density of the 35% HCl solution: The density of HCl solutions can vary depending on the concentration, temperature, and other factors. Typically, the density of a 35% HCl solution is around 1.18 g/mL.
2. Convert the percentage concentration into grams per milliliter (g/mL) or grams per liter (g/L): Since the density is given in grams per milliliter, we will use g/mL. For a 35% HCl solution, if we have 100 mL of the solution, it would contain 35 grams of HCl. Therefore, the solution has a density of 35 g/100 mL or 0.35 g/mL.
3. Convert the grams of solute (HCl) into moles: To do this, we need to know the molar mass of HCl, which is approximately 36.46 g/mol. Divide the mass of HCl by its molar mass:
moles of HCl = (mass of HCl) / (molar mass of HCl)
For example, if we have 1 L of the 35% HCl solution and using the density of 0.35 g/mL, then the mass of HCl would be 0.35 g/mL * 1000 mL = 350 g. Dividing this by the molar mass of HCl:
moles of HCl = 350 g / 36.46 g/mol = 9.59 mol
4. Calculate the molarity: Finally, divide the moles of HCl by the volume of the solution in liters:
Molarity (M) = (moles of HCl) / (volume of solution in liters)
For example, if we have 1 L of the 35% HCl solution, the molarity would be:
Molarity (M) = 9.59 mol / 1 L = 9.59 M
Therefore, the molarity of a 35% HCl solution would be 9.59 M.