Calculate the final concentration for the standardization of KMnO4 given this information:
2MnO4- + 5C2O4^-2 + 16H+ -> 2Mn^2+ + 10CO2 + 8H2O [final redox equation]
Volume of KMnO4 titrated with H2SO4 + Na2C2O4 = 293 mL
Volume KMnO4 titrated with H2SO4 alone = 0.2 mL
Amount of Na2C2O4 = 0.103 g
It says that I'd need that information to calculate the concentration but I'm confused since Na2C2O4 isn't even a part of that redox equation.. Please help!
Oh but it is. Na2C2O4 is where the 5C2O4^2- comes from.
293 mL-0.2 mL = 292.8 mL KMnO4 to titrate the Na2C2O4.
mols Na2C2O4 = grams/molar mass
Now convert mols Na2C2O4 to mols KMnO4 using the coefficients in the balanced equation.
Then M KMnO4 = mols KMnO4/L KMnO4.
Post your work if you get stuck.
Hi DrBob
0.103 g Na2C2O4 divided by 134 g/mol Na2C2O4 = 0.000768 mol Na2C2O4 = 0.000768 mol KMnO4
0.000768 mol C2O4^-2 X 2 mol MnO4-/5 mol C2O4^-2 = 0.0003072 mols KMnO4
M KMnO4 = 0.0003072 mol/0.293 L = 0.001048 M..? is that right? close? or totally wrong?
partially right, partially wrong.
My calculator reads 0.0007688 for mol Na2C2O4 so I would round that to 0.000769.I think you threw the last digit away.
Then you must convert mols Na2C2O4 to mols KMnO4.
0.000769 mols Na2C2O4 x (2 mols KMnO4/5 mols Na2C2O4) = 0.000769 x 2/5 = 0.000307 as you have. Note that your previous statement that 0.000769 mol Na2C2O4 = 0.000768 mol KMnO4 is not right and in fact it doesn't belong anywhere in the solution.
Then M = mols/L = 0.000768/.2928 L = 0.001048 which I would round to 0.00105 M.
So except for the rounding your answer is right although there were a few missteps along the way.
Ohh yeah it was actually my fault DrBob i wrote 293 mL but it was actually 2.93 mL but i still got it after your explanation. THANK YOU!!!!
To calculate the final concentration for the standardization of KMnO4, you need to use the balanced redox equation provided:
2MnO4- + 5C2O4^-2 + 16H+ -> 2Mn^2+ + 10CO2 + 8H2O
Although Na2C2O4 (sodium oxalate) is not directly involved in the redox equation, it is used as a titrant to determine the concentration of KMnO4 by a redox titration. The reaction between KMnO4 and Na2C2O4 can be represented as follows:
2KMnO4 + 5Na2C2O4 + 8H2SO4 -> 2MnSO4 + 10CO2 + K2SO4 + 8H2O + 5Na2SO4
In this reaction, KMnO4 reacts with Na2C2O4 to produce MnSO4, CO2, and other products. The purpose of adding H2SO4 is to provide a suitable environment for the redox reaction to occur.
Now let's calculate the concentration of KMnO4 using the given information:
1. Convert the given mass of Na2C2O4 into moles:
Moles of Na2C2O4 = (0.103 g) / (molar mass of Na2C2O4)
2. Calculate the molarity of Na2C2O4:
Molarity of Na2C2O4 = (moles of Na2C2O4) / (volume of Na2C2O4 used in titration)
3. Use stoichiometry to determine the number of moles of KMnO4 reacted with Na2C2O4:
Moles of KMnO4 = 5 * (moles of Na2C2O4)
4. Calculate the initial concentration of KMnO4:
Initial concentration of KMnO4 = (moles of KMnO4) / (volume of KMnO4 used in titration with H2SO4 alone)
5. Determine the final concentration of KMnO4:
Final concentration of KMnO4 = Initial concentration of KMnO4 * (volume of KMnO4 titrated with H2SO4 + Na2C2O4) / (volume of KMnO4 titrated with H2SO4 alone)
Remember to convert the volumes from milliliters to liters before performing calculations.
By following these steps and plugging in the given values, you should be able to calculate the final concentration of KMnO4 for standardization.