URGENT!!! Sulfate content of lawn fertiliser question. (1 Viewer)

[Lilizzy1939]

I've been doing revision of all the practicals for chem. In this experiment, my class dissolved 1g of ammonium sulfate in distilled water to make up 100mL and then added silver nitrate. All the textbooks and resources I have say to use hydrochloric acid instead. I'm soo confused, did we do it wrong?

 

[Hi there444]

I've been doing revision of all the practicals for chem. In this experiment, my class dissolved 1g of ammonium sulfate in distilled water to make up 100mL and then added silver nitrate. All the textbooks and resources I have say to use hydrochloric acid instead. I'm soo confused, did we do it wrong?

The hcl is to dissolve but the agno3 is to form the agso4 precipitate which can be filtered and then through gravimetric analysis the mass of sulfate can be found. If you didnt add HCL that is probably because if you added agno3 then agcl is insoluble affecting validity greatly. You probably added nitric acid to dissolve or such? If not then exp is invalid cos not all fertiler would have been dissolved.

 

[MaccaFacta]

It sounds like you used some ammonium sulfate off the shelf from the chemical storeroom rather than a fertiliser mix from a supermarket or a hardware shop. If this is the case, then the ammonium sulfate would have all dissolved in the water pretty easily, so there would have been no need to add nitric or (as all the books you've been reading say) hydrochloric acid to get the last few lumps of fertiliser to dissolve. This just means that your class did a simplified version of the reaction. Simple is good. I'm guessing that you precipitated silver sulfate, filtered it out, dried it, weighed it and calculated how much sulfate there was in the original 1.0 g? If you know how to calculate the masses and the moles, then you are right on track.