If 26.223 mL of potassium permanganate solution is required to titrate 1.041 g of ferrous ammonium sulfate hexahydrate, { FeSO4(NH4)2So46H2O }, calculate the molarity of the KMno4 solution.
and the equation the lab gave me was
Mn04(-) + 8H(+) + 5Fe(+2) ----> Mn(2+) + 4H2O + 5 Fe(+3)
1. calculate the molecular mass of the ferrous salt. RMM
2. calculate the number of moles of ferrous salt. 1.041/RMM
3. from the equation 1 mole of permanganate reacts with five moles of the ferrous salt, hence the number of moles of permanganate is 1/5 of the number of moles of ferrous salt.
4. 26.223 ml is 0.026223 L. So the molarity of the permanganate solution is the number of moles from step 3 divided by 0.026223 L.
Does this make sense?
Yes but I come up like this
MW Fe = 55.845 divided by 342.0 = 0.16329 Moles of Fe
If 1 mole of KMnO4 is used for 5 Moles of Fe then Moles of KMnO4 = .03268 M
Molarity = Moles/Liter
Moles of KMnO4 = .03268 Moles
and 26.223 mL / 1000mL/Liter = .02633 L
Then answer should be around 1.241
55.845 / 342.0 =0.16329 moles Fe
/5 = .03268
/ .026223 = 1.245 M/L =1.245 M
Why 55.845/342?
1. I get the RMM to be 392 g mol-1 (please check my maths!)
So step 2. is
1.041g/392 g mol-1 = moles
which gives you the number of moles of Fe in the starting mass of the salt.
Now go from here....
That is what I get too.
But after dividing the concentration by 5 I get an answer of 1.245M
The answer is wrong! Or the teacher gave us the wrong answer.....
I was wondering if you (we) got the answer correct - I figure the RMM of the FASH to be to be 392g,mole .... so the 1.041g/392g/mole = number of moles. Then the number of moles of KMnO4 is 1/5 of that and then the rest is easy.
Number of moles of Fe = 55.845 / 392 = .142461734 Moles Fe
Number of moles of KMnO4 is .142461734 / 5 moles of Fe per mole KMnO4 = .028492346 Moles KMnO4
Molarity of solution is Moles/liter = .028492346 moles KMnO4 / .026223 liters KMnO4 = 1.09 Molar
I was wondering if you (we) got the answer correct - I figure the RMM of the FASH to be to be 392g,mole .... so the 1.041g/392g/mole = number of moles. Then the number of moles of KMnO4 is 1/5 of that and then the rest is easy.
Number of moles of Fe = 55.845 / 392 = .142461734 Moles Fe
Number of moles of KMnO4 is .142461734 / 5 moles of Fe per mole KMnO4 = .028492346 Moles KMnO4
Molarity of solution is Moles/liter = .028492346 moles KMnO4 / .026223 liters KMnO4 = 1.09 Molar maybe. LOL KUS UMAK IL MITNAKAH
To calculate the molarity of the KMnO4 solution, we need to use the balanced equation provided and the volume of KMnO4 solution used.
The balanced equation is:
MnO4(-) + 8H(+) + 5Fe(+2) -> Mn(2+) + 4H2O + 5Fe(+3)
From the equation, we can see that the mole ratio between KMnO4 and FeSO4(NH4)2SO4·6H2O is 1:5. This means that for every one mole of KMnO4, we need 5 moles of FeSO4(NH4)2SO4·6H2O.
Given that 26.223 mL of KMnO4 solution is required to titrate 1.041 g of FeSO4(NH4)2SO4·6H2O, we need to convert this amount to moles.
First, calculate the molar mass of FeSO4(NH4)2SO4·6H2O:
Fe: 55.85 g/mol
S: 32.07 g/mol
O: 16.00 g/mol (x 10 atoms in the formula)
N: 14.01 g/mol (x 2 atoms in the formula)
H: 1.01 g/mol (x 12 atoms in the formula)
Molar mass of FeSO4(NH4)2SO4·6H2O = (55.85 g/mol) + (32.07 g/mol) + (16.00 g/mol x 10) + (14.01 g/mol x 2) + (1.01 g/mol x 12) = 392.14 g/mol
Next, convert the mass of FeSO4(NH4)2SO4·6H2O to moles:
Moles = mass / molar mass = 1.041 g / 392.14 g/mol
Once we have the moles of FeSO4(NH4)2SO4·6H2O, we can find the moles of KMnO4 used in the titration, using the mole ratio from the balanced equation. Since the molar ratio of FeSO4(NH4)2SO4·6H2O to KMnO4 is 5:1, the moles of KMnO4 used will be 1/5th of the moles of FeSO4(NH4)2SO4·6H2O.
Moles of KMnO4 = (1/5) x (1.041 g / 392.14 g/mol)
Finally, calculate the molarity of the KMnO4 solution:
Molarity = moles of KMnO4 / volume of KMnO4 solution (in liters)
First, convert the volume of KMnO4 solution from mL to L:
Volume = 26.223 mL / 1000 mL/L
Now, substitute the calculated values into the equation:
Molarity = (moles of KMnO4) / (volume of KMnO4 solution in liters) = (moles of KMnO4) / (26.223 mL / 1000 mL/L)
Calculate the moles of KMnO4 first, then substitute it into the equation to find the molarity.