ok for a lab we had to titrate a solution with KMnO4 and for each trial i got 22.83 mL,23.92, and 22.48
I need to find the mass percent of the oxalate ion. How would I do this?
The equation is MnO4-+C2O4 2- -> Mn 2+ + CO2
In the lab we used about .1 g of the oxalate salt in each titration.
forget to tell u that the M of KMnO4 is .011393M
About 0.1 g of the oxalate salt won't do it if you're looking for any kind of quantitative answer. And with buret readings to the second place, you must be looking for a decent answer.
First balance the equation.
Have you determined the molarity of the KMnO4? or is that the purpose of the about 0.1 oxalate ion? I will assume you have the molarity and go from there. If not, then what follows is not correct.
Find mols KMnO4. That will be M x L = ??
(You don't list the molarity but I'm sure you have it there somewhere.)
Then use the balanced equation to convert mols KMnO4 to mols oxalate.
Convert mols oxalate ion to grams oxalate ion.
Then %oxalate = [(grams oxalate)/mass of the initial sample)]*100
To find the mass percent of the oxalate ion, you need to determine the amount of oxalate reacted with KMnO4 in each trial. Once you know the amount reacted, you can calculate the mass of the oxalate ion and then determine its percentage in the total mass.
Here's the step-by-step process:
1. Calculate the average volume of KMnO4 used in the titration:
Add up the volumes of KMnO4 used in each trial (22.83 mL + 23.92 mL + 22.48 mL) and divide the sum by the number of trials (3).
Average volume = (22.83 mL + 23.92 mL + 22.48 mL)/3
2. Calculate the number of moles of KMnO4 used:
The molarity of KMnO4 can be determined based on the stoichiometry of the reaction. If you know the concentration of KMnO4, use the formula:
Moles of KMnO4 = Molarity (in mol/L) × volume (in L)
3. Determine the molar ratio between KMnO4 and C2O4^2-:
The balanced equation for the reaction shows that one mole of KMnO4 reacts with one mole of C2O4^2-. This means the molar ratio is 1:1.
4. Calculate the number of moles of C2O4^2-:
Since the molar ratio between KMnO4 and C2O4^2- is 1:1, the number of moles of C2O4^2- is equal to the number of moles of KMnO4.
5. Determine the mass of the oxalate ion:
The molar mass of the oxalate ion (C2O4^2-) is calculated by determining the sum of the atomic masses of carbon (12.01 g/mol), oxygen (16.00 g/mol), and multiplying by 2 (since there are two atoms of oxygen in the ion).
Molar mass of C2O4^2- = (12.01 g/mol + 16.00 g/mol) × 2
6. Calculate the mass percent of the oxalate ion:
Mass percent = (mass of C2O4^2- / total mass) × 100
The total mass in this case is the mass of the oxalate salt used in the titration (0.1 g).
Finally, substitute the values into the appropriate formulas and perform the calculations to find the mass percent of the oxalate ion.
Note: Make sure you are using accurate values for the molarity of KMnO4, and if any other sources of error occurred during the titration, take those into account while interpreting the results.