commercially available concentrated H CL contains 38% H CL by mass
(a) what is the molarity of this solution if the density in 1.19gm/l
(b) what volume of concentrated HCL is required to make 1l of 0.1M HCL?
molarity=moles/volume
assume 1.000 liters, 1190grams.
of that, .38*1190 = mass HCL
moles HCl= massHCl/38
figure molarity from that. I get about 12M
Now, knowing the original molarity, say it is 12 (you better work that out),
then you are trying to dilute it 12/.1 or 120 times, which means one part original, 119 parts water.
Whatis 1 Part? 1000cc/120=8.333 cc
To solve these questions, we can use the following formulas and relationships:
1. Molarity (M) = moles of solute / volume of solution (in liters).
2. Moles of solute = mass of solute / molar mass of solute.
3. Density (D) = mass of solution / volume of solution.
(a) To find the molarity of the solution:
Given:
Concentration of HCl = 38% by mass.
Density = 1.19 g/mL.
First, we need to convert the density to g/L:
Density = 1.19 g/mL * 1000 mL/L = 1190 g/L.
Next, we need to calculate the moles of HCl present in 100 g of the solution:
Moles of HCl = (mass of HCl / molar mass of HCl) * (100 g / 100%).
The molar mass of HCl is 1 g/mol for hydrogen plus 35.5 g/mol for chlorine, giving us a total of 36.5 g/mol.
Moles of HCl = (38 g HCl / 36.5 g/mol) * (100 g / 100%) = 104.11 mol.
Now we can calculate the volume of the solution:
Molarity = Moles of HCl / Volume of solution (in liters).
Molarity = 104.11 mol / (1000 g / 1190 g/L) = 0.1298 M.
Therefore, the molarity of the solution is 0.1298 M.
(b) To calculate the volume of concentrated HCl required:
Given:
Molarity of HCl solution = 0.1 M.
Volume of HCl solution = 1 L.
We can rearrange the formula for molarity to solve for moles of solute:
Moles of HCl = Molarity * Volume of solution (in liters).
Moles of HCl = 0.1 M * 1 L = 0.1 mol.
Now, let's calculate the mass of HCl required:
Mass of HCl = Moles of HCl * Molar mass of HCl.
Mass of HCl = 0.1 mol * 36.5 g/mol = 3.65 g.
Since the concentration of the commercially available HCl is 38% by mass, we can set up the following equation:
Mass of HCl / Mass of concentrated HCl solution = 38%.
Mass of HCl solution = (Mass of HCl) / (38%).
Mass of HCl solution = (3.65 g) / (0.38) = 9.61 g.
Finally, let's calculate the volume of concentrated HCl required:
Volume of concentrated HCl = Mass of HCl solution / Density.
Volume of concentrated HCl = 9.61 g / 1.19 g/mL = 8.08 mL.
Therefore, approximately 8.08 mL of concentrated HCl is required to make 1 L of 0.1 M HCl solution.