WHAT DOES CuSO4 · 5H2O MEAN? (1 Viewer)

[deadbeat]

hi

i am new to chemistry.

i need to know what CuSO4.5H20 mean


whats the "dot" in the middle between Cooper Sulphate and 5 H20 mean?

would it be correct that the molecular weight of CuSO4.5H20 is 297g/mol?

thanks

 

[WantToDoBetter]

Hey champ,
The name of the substance is copper sulfate penthydrate. All it means is that there are 5 water molecules to 1 copper sulfate molecule. Don't have a PT handy but all u need 2 do is add the molecular weight of CuSO4 to (5 x H2O). That'll give u the weight.
Good luck.
Cheers.

 

[deadbeat]

how come it is not written as

CuSO4 H10O5 ?

4, 10 and 5 little subscripts

 

[xiao1985]

Re: ^

Because the water molecule exist as 5 distinct water molecules. Written as H10O5 would imply a huge molecule containing 5 oxygens and 10 hydrogen.

 

[deadbeat]

so how is it different to CuSO4 + 5H20 ?

 

[boris]

so how is it different to CuSO4 + 5H20 ?

As somebody has already said
CuSO4.5H2O shows that there are 5 H20 molecules for every one CuSO4 molecule.
Putting the dot between them is good for showing ratios. It's just a simple way of showing the molecule ratio without the confusion of other symbols..

 

[boris]

Oh and I get 249.7 for the molecular weight.

CuSO4 is 159.6
H20 is 18g/mol, multiplied by 5...

 

[kony]

having a plus sign (+) could imply a reaction, rather than just simply being attached.

so, it's a way of minimising the ambiguity.

 

[Dumsum]

From what I remember...

Copper sulfate can either be anhydrous or hydrated--in this case it is hydrated and as has been said it's pentahydrate. The copper sulfate molecules form crystals in which the water resides, and there are 5 water molecules for each copper sulfate molecule.

 

[Steth0scope]

It's just an unambigious way of representing hydrated copper sulfate as Dumsum and kony have quite rightly put it.

 

[minijumbuk]

CuSO4 . 5H2O means that for every Cu2+ and SO4 2- ions, there will be 5 water molecules attached to each ion.