A 25.0-mL solution of 0.0660 M EDTA was added to a 33.0-mL sample containing an unknown concentration of V3 . All V3 present formed a complex, leaving excess EDTA in solution. This solution was back-titrated with a 0.0450 M Ga3 solution until all the EDTA reacted, requiring 13.0 mL of the Ga3 solution. What was the original concentration of the V3 solution?

EDTA reacts with both V3+ and Ga3+ in a 1:1 stoichiometric ratio.

Therefore, the moles of EDTA added is equal to the sum of the moles of V3+ present and Ga3+ added.
moles of EDTA= moles V3 + moles of Ga3
(0.025 L)(0.0660 M EDTA)= (x moles of V3) + (0.013 L)(0.0450 M Ga3)
moles of V3= 0.001065
M of V3 = 0.001065 moles / 0.033 L
M of V3 = 0.032 moles/L

Why did the V3 solution go to therapy? It had some serious concentration issues! But don't worry, I'm here to help. Let's work through this step by step.

First, we need to determine how much EDTA was used in the reaction. Since the V3 solution reacted completely, any excess EDTA must have reacted with the Ga3 solution during the back-titration. So, the amount of EDTA used can be calculated by subtracting the volume of Ga3 solution used (13.0 mL) from the total volume of EDTA solution added (25.0 mL).

25.0 mL - 13.0 mL = 12.0 mL

Next, we need to calculate the number of moles of EDTA used. We can use the molarity of the EDTA solution (0.0660 M) to do this. Remember, moles = volume * concentration.

moles of EDTA = 0.0660 M * (12.0 mL / 1000 mL/mL) = 0.000792 mol

Since the stoichiometry of the reaction is 1:1 between EDTA and V3, the number of moles of V3 present in the original sample is also 0.000792 mol.

Now we can calculate the concentration of the V3 solution. We'll use the volume of the V3 solution (33.0 mL) and the number of moles of V3.

concentration of V3 = 0.000792 mol / (33.0 mL / 1000 mL/mL) = 0.024 M

So, the original concentration of the V3 solution was 0.024 M. Isn't it amazing what a little bit of math can do?

To find the original concentration of the V3 solution, we can use the concept of stoichiometry and the balanced chemical equation between EDTA and V3.

The balanced chemical equation is as follows:

1 EDTA + 1 V3 -> 1 EDTA-V3 complex

Based on the information given in the problem:

Volume of EDTA solution = 25.0 mL
Concentration of EDTA solution = 0.0660 M
Volume of Ga3 solution used in back titration = 13.0 mL
Concentration of Ga3 solution = 0.0450 M

Before proceeding further, let's determine the number of moles of EDTA used in the reaction:

moles of EDTA = volume of EDTA solution * concentration of EDTA solution
= 25.0 mL * 0.0660 M
= 1.65 mmol

Since 1 mole of EDTA reacts with 1 mole of V3, we can conclude that 1.65 mmol of V3 was complexed in the reaction.

Next, let's determine the number of moles of Ga3 involved in the back titration:

moles of Ga3 = volume of Ga3 solution used * concentration of Ga3 solution
= 13.0 mL * 0.0450 M
= 0.585 mmol

Since 1 mole of Ga3 reacts with 1 mole of EDTA, we can conclude that 0.585 mmol of EDTA was present in the solution.

Now, we can determine the excess moles of EDTA remaining after the reaction:

excess moles of EDTA = moles of EDTA used - moles of EDTA from Ga3
= 1.65 mmol - 0.585 mmol
= 1.065 mmol

Finally, we can calculate the concentration of V3 in the original solution:

concentration of V3 = excess moles of EDTA / volume of sample
= 1.065 mmol / 33.0 mL
= 0.0323 M

Therefore, the original concentration of the V3 solution is 0.0323 M.

To find the original concentration of the V3 solution, we can use the concept of stoichiometry in a chemical reaction.

First, let's write the balanced chemical equation for the reaction between EDTA and V3:

V3 + EDTA → [Complex]

From the equation, we can see that the stoichiometric ratio between V3 and EDTA is 1:1. This means that for every 1 mole of V3, we need 1 mole of EDTA to react completely.

Now, let's calculate the amount of EDTA used in the titration. We know the volume of the EDTA solution used is 25.0 mL, and the concentration of the EDTA solution is 0.0660 M. We can use the following equation to calculate the moles of EDTA used:

moles of EDTA = concentration of EDTA × volume of EDTA solution
= 0.0660 M × 25.0 mL
= 1.65 mmol

Since the stoichiometric ratio of V3 to EDTA is 1:1, the amount of V3 present in the sample would also be 1.65 mmol.

Next, let's calculate the moles of Ga3 used in the back-titration. We know the volume of the Ga3 solution used is 13.0 mL, and the concentration of Ga3 solution is 0.0450 M. We can use the same equation as before to calculate the moles of Ga3 used:

moles of Ga3 = concentration of Ga3 × volume of Ga3 solution
= 0.0450 M × 13.0 mL
= 0.585 mmol

Since the stoichiometric ratio between Ga3 and EDTA is 1:1, this means that 1.65 mmol of EDTA reacted, requiring 0.585 mmol of Ga3.

Finally, we can calculate the original concentration of the V3 solution by dividing the moles of V3 by the volume of the V3 solution used:

original concentration of V3 = moles of V3 ÷ volume of V3 solution
= 1.65 mmol ÷ 33.0 mL
= 0.0500 M

Therefore, the original concentration of the V3 solution is 0.0500 M.