Calling Chem Majors!

[kap]

S/O is stuck on this chem problem I cannot help because it's been soooo long ago that I took general chem :-( Here is the problem: In the following reaction, 3g of CaCO3 is heated to produce CaO and CO2. How many grams of CO2 could be produced if all the CaCO3 is used up? TiA

Kap

[Webster J. Duck]

1.3 gm

[kap]

Thanks Webster for the quick response. However, we'd like to know the steps you took to arrive to the solution. Thanks again

Kap

[Webster J. Duck]

1 mol ofCaCo3 should generate 1 mol of CO2 and 1 mol of CaO by the stoichiometry presented. Since the molecular weight of CaCO3 is approximately 100 you start with 0.03 mol (or 30 mmol) of CaCO3. And since the molecular weight of CO2 is about 44 you end up with 1.3 gm or 0.03 mol of CO2. The next question probably has a more complex stoichiometry...determine the number of mols produced and multiply by the molecular weight.

Or since it’s a 1:1 stiochiometry you could have just tried (44/100)*3=1.3 gm.

[bangman]

Man, you can learn some crazy stuff here in the forums.

[MacMagus]

Here's how I would solve it.

CaCO3 + HEAT == CaO + CO2

CaCO3 weighs 3g TOTAL, but that breaks down into x percentages by atomic weight...

Ca = 40.078
C = 12.0107
O = 15.9994
O = 15.9994
O = 15.9994

So one molecule would weigh roughly 40 + 12 + (16 * 3) = 100. Call that 100% and you'll see that the weight of each atom translates very easily into a percentage. CO2 would then weigh (12 + 16 + 16) or 44% of the whole.

44% of 3g is 1.32g.

[Edit] Damn! I'm typing slowly tonight.

[wurm]

I remember that Fe is iron. Any points for that?

[kap]

She's got it! Webster and MacMagus, you guys are "awesome!" THose were her words.

I am with wurm

Kap

[Pops]

[quote bangman] Man, you can learn some crazy stuff here in the forums.
You might be able to learn it... I have enough difficulty reading it. Far, far too many years between chem and now.

[MikeF]

It wasn't unitl I took chemistry that one of the mysteries in my childhood was finally solved...

You know how you add Nestle's Quik to milk, and as a kid, you just keep adding more and more and it doesn't really dissolve after a certain point and you end up with a bunch of sludge at the bottom...

Well... Molar/molecular constant (sp?)...