back again with another analytical Q,
the question tells you to prep a 50 mL solution of a 750 ppm iron solution using ammonium iron III oxalate trihydrate (MM: 428.06 as a source of iron. Determine the mass of compound required.
I'm assuming you would start with a molarity calculation, M = mol / L, converting 750 ppm iron to moles of the ammonium compound and then to grams. Is this the way to go?
I would not go that way. When dealing with ppm I remember one very nice factor to keep in mind; i.e., 1 ppm = 1 mg/L.
So 750 ppm = 750 mg/L. You want 50 mL so that is 750 x 50 mL/1000 mL = 37.5 mg Fe = 0.0375 g Fe you want. Convert that to the oxalate trihydrate and you have it. I think it's way simpler that way.
Thanks sir! :)
Yes, you are on the right track. To determine the mass of the ammonium iron III oxalate trihydrate required to prepare a 50 mL solution of a 750 ppm iron solution, you need to follow a series of steps.
Step 1: Calculate molarity of iron (Fe) in the 750 ppm solution.
Molarity (M) is defined as moles of solute divided by the volume of the solution in liters.
First, convert 750 ppm (parts per million) to a decimal fraction. Since ppm is equivalent to mg/L, 750 ppm is equal to 750 mg/L.
Then, convert mg/L to grams/L by dividing by 1000 since there are 1000 mg in a gram.
Now, we have the mass of iron (Fe) in grams per liter (g/L).
Finally, divide this mass by the molar mass of iron (Fe) to get the moles of iron (Fe) per liter (mol/L).
Step 2: Convert moles of iron to moles of ammonium iron III oxalate trihydrate.
The equation of ammonium iron III oxalate trihydrate is (NH4)3Fe(C2O4)3·3H2O. By examining the balanced equation, you can determine the molar ratio between iron (Fe) and ammonium iron III oxalate trihydrate.
Step 3: Convert moles of ammonium iron III oxalate trihydrate to grams.
Using the molar mass of ammonium iron III oxalate trihydrate (MM: 428.06 g/mol), multiply the number of moles by the molar mass to get the mass in grams.
Finally, by performing these calculations, you will find the mass of ammonium iron III oxalate trihydrate required to prepare a 50 mL solution of a 750 ppm iron solution.