If a 2.893 gram sample of an unknown containing iron requires 28.45 mL of the potassium permanganate solution to reach the endpoint, calculate the % Fe in the unknown.

Question

jfraser · Answer

You need to know:

the volume of $KMnO_4$ solution used

the concentration of the $KMnO_4$ solution used

the mole ratio from the balanced rection

cometailcane · Answer

ok so would the volume used be 28.45? I know the concentration is 0.2502 and the balanced equation is

cometailcane · Answer

$$MnO _{4}^{-} + 8H ^{+} + 5Fe ^{2+} = Mn ^{2+} + 4H _{2}O + 5Fe ^{3+}$$

cometailcane · Answer

@JFraser

jfraser · Answer

so far so good. Use the volume and the concentration of the permanganate solution to find the moles of permanganate used. Then use the mole ratio to find the moles of iron reduced. That should be less than the mass of the original iron sample, and you can find the percentage