[murmelburmel]

Hi,
in a simple experiment my measured yield doesn't match the theoretical one, I have too much product.

The reaction is: FeCl₃*6H₂O +Na₂HPO₄  --> FePO₄ + 2NaCl + HCl

n_{ferric chloride hexahydrate} = 1g (amount used) / 270 g/mol (molar mass) = 0.0037 mol

For Na₂HPO₄ using the same formula and 0.72g substance used I get n = 0.0051 mol

So the amount of ferric chloride is limiting and one part ferric chloride reacts with one part Na₂HPO₄ to one part FePO₄.

But calculating yield (m) with m=n(ferric chloride)*M(FePO₄) only gives me 0.55g, while in reality I measured around 1g yield.

I'm not a chemistry student and a complete beginner in chemistry so unsure where it went wrong. Is the reaction formula correct?

[mjc123]

Sounds like you haven't isolated pure product. Is it wet? Has it got NaCl mixed with it?

[murmelburmel]

I followed a script for the process. The product was filtrated, cleaned with distilled water, filtrated again and then dried in an oven. It's possible that there was NaCl in it (didn't test for it sadly) but I find it hard to believe it would amount to almost half the weight of the product.
So the theory is theoretically correct, right?

Thanks, btw!

[Borek]

So the theory is theoretically correct, right?

Technically the equation as given is not balanced (doesn't account for the water on the right hand side), and the rounding is off, but these are minor things that don't change much -  I got 0.56 g.

see https://youtu.be/bFD06DcqRGM

[murmelburmel]

see https://youtu.be/bFD06DcqRGM

Thanks for taking the time making that, much appreciated! Ok, I'll check with my teaching assistant, something must have gone wrong during synthesis or weighing.