What mass in grams of an aqueous hydrochloric acid solution that is 37.0% by mass hydrogen chloride is needed to supply 2.000 moles of hydrogen chloride?
37.0% w/w means 37.0g HCl/100 g soln. You want 2.00 moles x molar mass HCl = x g HCl.
100 g soln*(x g /37) = mass soln to be taken.
To calculate the mass of the hydrochloric acid solution needed, we can follow these steps:
Step 1: Identify the given information:
- Percent composition of the hydrochloric acid solution: 37.0%
- Number of moles of hydrogen chloride needed: 2.000 moles
Step 2: Convert the percent composition to a decimal:
37.0% = 0.370 (percent divided by 100).
Step 3: Calculate the mass of the hydrochloric acid solution:
To do this, we need to consider that the 37.0% represents the mass of hydrogen chloride (HCl) in the solution.
Mass of hydrogen chloride (HCl) = Percentage by mass × Mass of solution
Let's assume the mass of the hydrochloric acid solution is "x" grams.
Mass of hydrogen chloride (HCl) = 0.370 × x
Step 4: Determine the molar mass of hydrogen chloride (HCl):
The molar mass of hydrogen chloride is equal to the sum of the atomic masses of hydrogen (H) and chlorine (Cl).
Molar mass of HCl = (1 × atomic mass of H) + (1 × atomic mass of Cl)
= 1.007 g/mol + 35.453 g/mol
= 36.460 g/mol
Step 5: Calculate moles of hydrogen chloride (HCl) using the given number of moles:
Moles = Mass / Molar mass
We are given that the number of moles of hydrogen chloride required is 2.000 moles.
2.000 moles = Mass / 36.460 g/mol
Step 6: Solve for the mass of the hydrochloric acid solution:
Mass = Moles × Molar mass
Mass = 2.000 moles × 36.460 g/mol
Mass ≈ 72.92 grams
Therefore, approximately 72.92 grams of the aqueous hydrochloric acid solution is needed to supply 2.000 moles of hydrogen chloride.