Stoichiometry...

[doberman_52]

I am completly lost in Chem right now. We are currently doing Stoichiometry... No clue on how to do this crap. I am hopeing somebody here can help me out a bit.
My problem:
How many moles of Ammonium Sulfate can be made from the reaction of 30.0 mol of NH3 with H2SO4 according to the following equation:
NH3 + H2SO4 -> (NH4)2 SO4

I have no idea as to how to set up the problem equation as far as the numbers go.

This is what I do know:


Number of moles given or mole ratio (what you want)
.................................................. what you have


This chemistry class sucks, we have almost no labs (around 5 in the last year), 99% lecture, no actual teacher here, like doing this online pretty much.

[GloriaJeans]

Alright, here it is...

30 mol NH3; 17g/mol NH3; so you have 30 x 17 = 510g NH3

According to your equation, 17.4g (or 1 mol) of NH3 produces 1 mol Ammonium Sulfate. And 1 mol Al. Sulfate is 132g. Thus...

510g NH3 x 1 mol (NH4)2 SO4......x 132g (NH4)2 SO4
..................17.4g NH3..................1 mol (NH4)2 SO4....So 30 mol NH3 made 3869 g of (NH4)2 SO4

But you need moles, so 3869/132 will give you 7.6 mol

Hope this helps!

[doberman_52]

Yea, it helps a bit. I just have about 30 more problems like this. So you convert the moles to grams find out that, then find out how much of the other chemical you have, then convert back to moles. This is going to be time consuming.

[GloriaJeans]

Once you get the concept, each problem should take you no longer than 2-3 minutes. The method is always the same...

[doberman_52]

Yea, usually math stuff doesn't take me to long if I get it.

[gouldie1903]

the coefficeints of the chemicals are the mole ratios. the equation must be balanced for these ratios to be true. for the equaion to be balanced there needs to be the same number of each type of chemicals on each side:

ex. 4 H on one side and 4 H on the other

the example you gave appears to already be balanced, but if it was not you would need to multiply the chemicals to balcance out the equation.

once the equation is balanced the coefficients is the mole ratio

in the example you gave the ratio says
1 mole + 1 mole will yeild 1 mole

hopefully this helps if you need clarification on anything let me know

[GloriaJeans]

That's a good point, but I don't think they're quite that far along yet...

[doberman_52]

Originally Posted by gouldie1903

the coefficeints of the chemicals are the mole ratios. the equation must be balanced for these ratios to be true. for the equaion to be balanced there needs to be the same number of each type of chemicals on each side:

ex. 4 H on one side and 4 H on the other

the example you gave appears to already be balanced, but if it was not you would need to multiply the chemicals to balcance out the equation.

once the equation is balanced the coefficients is the mole ratio

in the example you gave the ratio says
1 mole + 1 mole will yeild 1 mole

hopefully this helps if you need clarification on anything let me know

Ok, i miss understood that at first, We are passed balancing equations, but all of our equations are allready ballanced anyway, I think.

[Shpyder]

I flew threw Organic Chemsitry, Metabolic Biochemistry, and P-Chem at university...but I still can't do, and still fear, stoichiometry. This crap reduces my brain to scrambled eggs.

[doberman_52]

Originally Posted by Shpyder

I flew threw Organic Chemsitry, Metabolic Biochemistry, and P-Chem at university...but I still can't do, and still fear, stoichiometry. This crap reduces my brain to scrambled eggs.

Yeah, this is the hardest thing I've done for math/science and normally I have no problem at math anymore, kinda wierd.

[GloriaJeans]

Originally Posted by Shpyder

I flew threw Organic Chemsitry, Metabolic Biochemistry, and P-Chem at university...but I still can't do, and still fear, stoichiometry. This crap reduces my brain to scrambled eggs.

Yeah, organic was interesting...

[RalliArt3kGT]

The ONLY thing I remember from Chemistry last year is fuck stoichiometry. That crap raped my grade big time. I'm so glad I'm not going into any field where I need to use science.

[doberman_52]

Originally Posted by RalliArt3kGT

The ONLY thing I remember from Chemistry last year is fuck stoichiometry. That crap raped my grade big time. I'm so glad I'm not going into any field where I need to use science.

Me too.