posted by amber on .
Oxalic acid (H2C2O4) can be used to remove rust according to the following balanced equation:
Fe2O3 + 6H2C2O4 --> 2Fe(C2O4)33- +3H2O + 6H+
Calculate the number of grams of rust that can be removed by 5.00 x 102 ml of a 0.122M solution of oxalic acid.
I know i need to multiply the # of moles*6*160 (which is the molecular mass)
0.061 moles of oxalic acid.
so is it .061*6*160= 585.6
is that right i'm pretty sure its not
The oxalic acid solution contains
0.500 x 0.122 moles of oxalic acid.
As 6 moles of oxalic acid react with 1 moles of rust then 0.500 x 0.122 moles will react with
0.500 x 0.122 x 1/6 moles of rust
the MM for rust is 159.6882 g mole^-1
so the mass of rust is
0.500 x 0.122 x 1/6 x 159.6882 g
(3 sig figs are appropriate int he answer)
Your answer leaves me with 1.63 so is this wrong moles oxalic acid = 0.500 L x 0.122 M=0.610
the ratio between Fe2O3 and H2C2O4 is 1 : 6
moles Fe2O3 = 0.610/6=0.102
mass Fe2O3 = 0.102 mol x 159.69 g/mol=16.3 g
It left me with 16.3
You error is here
0.500 L x 0.122 M = 0.061 moles and NOT 0.610 moles
I got 1.63 g agreed
oh okay i got it