You are instructed to prepare 250 mL of a solution which is 50 M in NaCl and 0.10 M in acetic acid. Solid NaCl and a 3.0 M solution are avaliable. How would you prepare this solution?
Is that 50M NaCl or 0.50M NaCl?
How many mols NaCl do you need? That is M x L = ? Then mols = g/molar mass and solve for grams NaCl. Weigh out that much NaCl and add to a 250 mL volumetric flask.
How many mols acetic acid do you need? That is M x L = 0.1 x 0.250 = 0.025
You have 3M; how much do you need of that?
M = mols/L or L = mols/M = 0.025/0.1 = ?L and convert to mL.
Add the acetic acid and about 100 mL water, swirl until the NaCl has completely dissolved, then add water to the mark and mix thoroughly.
To prepare a 250 mL solution that is 50 M in NaCl and 0.10 M in acetic acid, you will need to determine the amount of solid NaCl and the volume of the 3.0 M solution required.
First, let's calculate the amount of solid NaCl needed:
1. Determine the molar mass of NaCl, which is 58.44 g/mol (sodium: 22.99 g/mol, chlorine: 35.45 g/mol).
2. Calculate the mass of NaCl needed using the formula: mass = moles × molar mass.
Molarity (M) = moles / volume (L)
Rearranging the formula gives: moles = Molarity × volume (L)
Since the desired molarity is 50 M, and the desired volume is 0.250 L, we can calculate the moles as follows: moles of NaCl = 50 M × 0.250 L = 12.5 mol.
3. Finally, calculate the mass of NaCl required: mass = moles × molar mass = 12.5 mol × 58.44 g/mol ≈ 732 g.
Next, let's determine the volume of the 3.0 M solution needed:
1. Rearrange the molarity formula to solve for volume: volume (L) = moles / molarity (M).
Since the desired molarity is 0.10 M, and the desired volume is 0.250 L, we can calculate the moles of acetic acid required as follows: moles of acetic acid = 0.10 M × 0.250 L = 0.025 mol.
2. Next, calculate the volume of the 3.0 M solution needed: volume = moles / molarity = 0.025 mol / 3.0 M ≈ 0.0083 L (or 8.3 mL).
To prepare the solution:
1. Weigh out 732 grams of solid NaCl using an analytical balance.
2. Add the solid NaCl to a container.
3. Measure 8.3 mL of the 3.0 M acetic acid solution using a graduated cylinder.
4. Add the measured acetic acid solution to the same container.
5. Add distilled water to the container until the final volume reaches 250 mL. Mix well to ensure complete dissolution.
Please note that handling chemicals should be done with caution and in accordance with safety protocols.