(7 points)
1. The reaction that you just witnessed in while doing your titration was: HCl + NaOH H2O + NaCl. This equation is balanced. Your unknown solutions contained HCl solutions of unknown concentrations, and your titrant was a 0.75 M solution of NaOH. Use the information from the lab to calculate the concentrations of HCl in your 2 unknown solutions. Assume we have 100 mL of each Unknown solution.
You don't have the entire problem copies. What you need is the volume of NaOH added in your titration but here is what you do.
mols NaOH = M x L. That's 0.75M x L you used in the titrant.
mols HCl = mols NaOH from above.
Then M HCl = mols HCl/L HCl. The problem says L HCl = 0.1 (i.e., 100 ml).
To calculate the concentration of HCl in your unknown solutions, you can use the concept of stoichiometry and the volume and molarity of NaOH used in the titration.
Here's how you can calculate the concentration of HCl in each unknown solution:
1. Note down the volume (V1) and molarity (M1) of NaOH used in the titration. In this case, the volume of NaOH used is not mentioned, so assume you used a certain volume of NaOH, let's say V1 = 25 mL, and the molarity of NaOH is 0.75 M.
2. From the balanced equation, you can determine the mole ratio between HCl and NaOH, which is 1:1. This means that for every mole of NaOH used, there is an equal number of moles of HCl present.
3. Calculate the number of moles of NaOH used in the titration. This can be done using the formula:
Moles of NaOH = Volume of NaOH (in L) x Molarity of NaOH.
In this case, convert V1 from mL to L by dividing it by 1000.
Moles of NaOH = (V1/1000) L x 0.75 mol/L.
4. Since the mole ratio between HCl and NaOH is 1:1, the number of moles of HCl in the unknown solution is also equal to Moles of NaOH.
5. Now, calculate the concentration of HCl in the unknown solution. Remember that the volume of the unknown solution used in the titration is 100 mL.
Concentration of HCl = Moles of NaOH / Volume of HCl solution (in L).
HCl solution volume = 100 mL = 100/1000 L.
Concentration of HCl = Moles of NaOH / (100/1000) L.
6. Repeat steps 1-5 for both unknown solutions, using the respective volumes and moles of NaOH used in the titrations.
By following these steps, you can calculate the concentrations of HCl in your two unknown solutions. Remember to adjust the assumed volume of NaOH and perform the calculations accordingly if the actual volume used is different.