[indiegirl]

A certain mass of copper (II) carbonate was dissolved in a slight excess of dilute acid. The resultant solution was concentrated. It finally produced 10g of copper sulfate pentahydrate. What is the mass of copper(II) carbonate?

How would you do this? i understand you need to find the no. of moles of the known (copper sulfate pentahydrate), and then use equation co-efficient to find the no. moles of the unknown, but i don't know what the coefficients are. Apparently heat factors into it somewhere, but im not sure how this is done.

I would be grateful for any help

[Arkcon]

How would you do this? i understand you need to find the no. of moles of the known (copper sulfate pentahydrate)

A great first step, while you're doing that, the answer may come to you, if not ...

, and then use equation co-efficient to find the no. moles of the unknown, but i don't know what the coefficients are.

You're looking for an equation that correlates moles of product to moles of reactant.  Have you ever seen something called an "equation" that does this?  I'll bet you have, you just haven't realized it's purpose in this regard, yet ...

Apparently heat factors into it somewhere, but im not sure how this is done.

I don't think so.

[indiegirl]

Ok thanks. im glad about the heat thing. stupid unhelpful friend.

well i understand how to figure this out using m=nM. Its just i can't balance the equation. I know the steps: find moles of known, using this and the co-efficients find moles of unknown, using moles of unknown find mass of unknown. I get that, i just don't know what the actual co-efficients are. Im having trouble balancing it.

This is all i could do:

CuCO3 + H2SO4 --> CuSO4 + H20 + CO2

I don't understand how copper sulfate pentahydrate is formed...?

[Arkcon]

Im having trouble balancing it.

This is all i could do:

CuCO3 + H2SO4 --> CuSO4 + H20 + CO2

I don't understand how copper sulfate pentahydrate is formed...?

Your product, is not correct.  Balancing atoms is not the step you perform, until you've written the correct product.  Copper sulfate heptahydrate is written exactly how?  Look up the name on google to find the correct formula, if you have to.

[indiegirl]

i know what the product is, i've tried many things i just don't know whats right.

CuCO3 + H2SO4 ---> CuSO4.5H20

I can't balance this.

CuCO3 + H2SO4 ----> CuSO4.5H20 + CO2

I can't balance this. Or maybe it can be balanced, i just can't do it.

CuCO3 + H2SO4---> CuSO4.5H20 + CO2 + H20

I can't balance this, and i've gotten desperate because this really makes no sense at all.

CuCO3 + H2SO4 ---> CuSO4.5H20

Are you saying i use this? Thats the first thing i did but i couldn't balance it, obviously because of the carbon dioxide. Then i added carbon dioxide and i couldn't balance it. So basically i know what to do and how to find the mass, i just don't know what equation to use and get the co-efficients from...?

[AWK]

Since stoichiometry of important reactants(CuCO3 and CuSO4)  in reaction
CuCO3 + H2SO4 = CuSO4 + H2O + CO2
is 1:1
you can state
1 mole CuCO3 form 1 mole of CuSO4.5H2O
Next step is

[indiegirl]

Oh, i think i figured it out.

CuCO3 + H2SO4 ---> CuSO4 + H20 + C02

because the resultant was concentrated...

CuSO4 + 5H20 ---> CuSO4.5H20

Is this how copper sulfate pentahydrate is formed? If so i know how to do it. I've done about 30 questions almost exactly like this, but with this one i wasn't sure how copper sulfate pentahydrate was formed. Basically i wasn't sure of the stoichiometric ratio between copper carbonate and copper sulfate pentahydrate.

Now i can see that its 1:1, right?

Thanks for helping btw

[Borek]

1:1 it is