Hydrochloric acid is sold as a concentrated acqueous solution.
If the molarity of HCl is 12.0 and its density is 1.18 g/ml. calculate
A) MOLALITY
B)THE % BY MASS OF HCl in the solution
m=12m,the mass % of HCl=37.12
To calculate the molality (A) and the % mass of HCl in the solution (B), we need to use the given molarity and density. Here's how:
A) Molality (m):
Molality is defined as the number of moles of solute per kilogram of solvent. In this case, the solute is HCl, and the solvent is water.
First, we need to calculate the moles of HCl in the solution:
Moles of HCl = Molarity × Volume (in liters)
Given that the molarity of HCl is 12.0 M, we convert this to molality by dividing by 1000 (to convert mL to L):
Moles of HCl = 12.0 mol/L × Volume (in L)
Next, we need to calculate the mass of water in the solution:
Mass of Water = Volume × Density × 1000 (to convert g/mL to g/L)
Given that the density of the solution is 1.18 g/mL, we convert this to g/L:
Mass of Water = Volume (in L) × Density (in g/mL) × 1000 (g/L)
Finally, we can calculate the molality using the formula:
Molality (m) = Moles of HCl / Mass of Water (in kg)
B) % by Mass of HCl:
The % by mass of HCl is the mass of HCl divided by the mass of the solution, multiplied by 100.
First, we need to calculate the mass of HCl in the solution:
Mass of HCl = Moles of HCl × Molar Mass of HCl
Given that the molar mass of HCl is approximately 36.46 g/mol, we can calculate the mass of HCl.
Finally, we calculate the mass of the solution by adding the mass of HCl to the mass of water.
% by Mass of HCl = (Mass of HCl / Mass of Solution) × 100
By following these steps, you can calculate the molality and the % mass of HCl in the solution.