Question

Sodium thiosulphate 'pentahydrate'. Supersaturation is when the solute is more than the solvent can handle, I don't get how this works since it was originally a solid until you melt it

Answer 1

There has to be some water involved I'm guessing from the pentahydrate

Answer 2

Do you melt it so that the water is gone thus it becomes very supersaturated since there is more solute than solvent?

Answer 3

not sure i understand the question

Answer 4

I am curious as how sodium thiosulphate pentahydrate works as a supersaturated solution

Answer 5

It starts of as grains, and when you melt it the solution is apparently supersaturated

Answer 6

Is it because you lose the water in the grains and thus the 'solute' being the sodium thiosulphate dominates the solution thus making it supersaturated?

Answer 7

well your definition of supersaturation is kind of incorrect, supersaturation is when you dissolve more solute into a solvent than you would normally be able to (typically by heating)

Answer 8

Oh I see so heating these grains

Answer 9

how does it become supersaturated

Answer 10

how does a solution in general become supersaturated?

Answer 11

When you heat it and there is a lot more solute than solvent within the solution

Answer 12

when you heat it you're able to add more solute and dissolve it, there amount of solute cannot change merely by heating it

Answer 13

does the solvent change?

Answer 14

okay if solvent is water, and you heat it, would the water evaporate and thus allow the solution to be supersaturated?

Answer 15

sorry I am just trying to understand this concept hope I'm not bombarding you with too many questions

Answer 16

nope, if you evaporate water there will be less solvent and therefore less space for solute molecules to enter the solution..

basically if you heat it up, you increase the space between the solvent molecules and the solute is able to enter those spaces

Answer 17

lol no worries

Answer 18

Okay I did an experiment where I melted sodium thiosulfate pentahydrate

Answer 19

it was originally in a form of grains

Answer 20

but once it completely melted it was supposely in a supersaturated state

Answer 21

how come? I didn't add more solute

Answer 22

well you don't have to add more solute to have a supersaturated solution, what it means is that there is more solute in the solution than there would otherwise be.

did you add water or just heat the grains up?

Answer 23

I just heated the grains up but does it have water or something in them originally since it's called sodium thiosulfate 'pentahydrate'

Answer 24

yeah it has 5 water molecules

penta= 5

so yeah, basically you heated it up, and melted it in it's own water but if you let it cool below it's melting point it will crystallize out of solution

Answer 25

http://www.chem-toddler.com/solutions-and-solubility/supersaturated-thiosulphate.html

Answer 26

i just googled it and this came up

Answer 27

I shook it when it just cooled and it crystalized really fast

Answer 28

one last thing can I say it was supersaturated before I melted it?

Answer 29

or is that not possible in a solid state

Answer 30

nope, those terms are only used for solutions

Answer 31

i think it's applicable to gases as well

Answer 32

okay awesome thank you for your help, really understand it a lot better now!

Answer 33

good stuff, dude!