[jdxboy88]

alright...i have this chemistry teacher that is soooo hard to understand cuz of her mexican/irish accent and she teaches at the fastest pace possible!!! but im trying to keep up as much as possible i've come to 1 problem that i cannot get and i even look over her lectures and its sooo hard i have never learned it completely...can any help me on this?

Carbon disulfide, CS2, can be made from coke (C) and sulfur dioxide, SO2:

                                                                                 3C + 2SO2 → CS2 + 2CO2

If the actual yield of CS2 is 80.6 percent of the theoretical yield, what mass of coke is needed to produce 950 g of CS2?

[enahs]

950g of CS2 is 80.6% of what? How many mols is that? How many mols of Coke is that?

[Sev]

950g of CS2 is 80.6% of what? How many mols is that? How many mols of Coke is that?

Then how many grams of coke is that?   

[jdxboy88]

everything i posted is what she had gave us to work with. Im guessing grams of coke is c for Carbon... i got confused but thats what i used. and its saying the actual yield is 80.6% of the Theoretical yield and the actual yield is with CS2. here it is again:

Carbon disulfide, CS2, can be made from coke (C) and sulfur dioxide, SO2:

3C + 2SO2 → CS2 + 2CO2

If the actual yield of CS2 is 80.6 percent of the theoretical yield, what mass of coke is needed to produce 950 g of CS2

[Sev]

Yield of coke is 950g.  This is 80.6% of the theoretical yield.  So work out the theoretical yield.

Then:

...How many mols is that? How many mols of Coke is that?

Then how many grams of coke is that?  

[jdxboy88]

yea how is coke 950g? this equation confuses me im confused on how to find theoretical and actual but also why would i need those two when i have to find how many grams of COKE i need for 950g of CS2.

what i had did was

950g CS2/ 1 mole CS2 /  3 mole C  / 12.01g C
             /76.15g CS2/1 mole CS2/1 Mole C

                                =449.5g C

Now i dont know if im starting this off correct but im thinking that answer is the theoretical yield. I dont know what to do next or...if this is even correct.

[Sev]

Sorry, when I wrote "coke", I meant CS2.

You need the theoretical yield of CS2 to work backwards to find out how many moles of coke you need.

theoretical yield = 950/0.806 = 1178.66g.  This is 15.48 mol.  From rxn eqn this means you will need 46.44 mol, or 557.74g of coke.

[jdxboy88]

oooooo so its

15.478 Mol CS2 / 3Mol C  / 12.01g C
                     1Mol CS2 / 1 Mol C

 = 557.67g C

Is that the answer? thats as far as i would go? so it takes 557.67g of C to produce 950g of cs2?

[Sev]

Yep, right answer  , but your working doesn't make much sense to me  .  I did 15.478 x 3 x 12.01.

[jdxboy88]

damn u made it seem so easy i understand it now though! appreciate it a lot! thank ya

[corrcorr]

yea on the same hw.. i need help for number 1..

Aluminum reacts with bromine to form aluminum bromide:

2Al + 3Br2 → 2AlBr3

If 25.0 g of Al and 100. g of Br2 react, and 60.9 g AlBr3 is recovered, what is the percent yield for the reaction?

can somebody help me out?