2 H2 + O2 -> 2 H2O

If 1 gram of H2 reacts with excess O2, how many grams of H2O will be produced?

How many grams of O2 are needed to react 1 g of H2?

If we mixed 5g H2 with 50g O2 what is the limiting reactant?

If we mixed 5g H2 and 50g O2 what is the theoretical yield of H2O in grams?

If we mixed 5g H2 and 50g O2 and produced 40g H2O what is the % yield of the reaction?

11/27/2007 12:35:38 PM

aids

11/27/2007 12:36:49 PM

Say you have 50 rocks and 20 cups.

If you need to put two rocks in each cup which one will you run out of first?



the answer is yes

[Edited on November 27, 2007 at 12:37 PM. Reason : .]

11/27/2007 12:37:13 PM

,

worse than

11/27/2007 12:37:18 PM

"grams"

11/27/2007 12:37:48 PM

^^^ so you're saying that in problem 3 the limiting reactant is H2?

[Edited on November 27, 2007 at 12:38 PM. Reason : -]

11/27/2007 12:38:18 PM

you have to convert the grams back to moles using then use the mole ratios.


if it were 2A + B -> A2B, then it makes a difference if 1 mole of A is 5g or 5000g because it would a different to react 50g of B.

[Edited on November 27, 2007 at 12:43 PM. Reason : penis shake]

11/27/2007 12:40:28 PM

By mass, the reaction is 2 parts H and 16 parts O (actually it's 4 and 32, but whatever). i.e. you need 8 times as much O as H.

If 1 gram of H2 reacts with excess O2, how many grams of H2O will be produced? 9 grams

How many grams of O2 are needed to react 1 g of H2? 8 grams

If we mixed 5g H2 with 50g O2 what is the limiting reactant? Hydrogen

If we mixed 5g H2 and 50g O2 what is the theoretical yield of H2O in grams? 45 g (5g of H plus 8 times as much O)

If we mixed 5g H2 and 50g O2 and produced 40g H2O what is the % yield of the reaction? 88.89% (8/9)

[Edited on November 27, 2007 at 12:43 PM. Reason : you don't need moles unless you are retarded]

[Edited on November 27, 2007 at 12:43 PM. Reason : why are you solving this problem. are we back in kindergarten?]

11/27/2007 12:42:30 PM

can you show some work?

I'm trying to understand this shit but I'm in a thought-coma cause I am sick/didn't sleep enough/am at work

^ its for a food chemistry class... I don't have a lot of experience with chemistry what with spending all of my time amongst the literature and philosophy departments

[Edited on November 27, 2007 at 12:44 PM. Reason : -]

11/27/2007 12:43:40 PM

if you can't read the book to figure it out or look online, you're retarded, and thus need moles.


Or if you were using more complicated substances.

11/27/2007 12:44:17 PM

http://en.wikipedia.org/wiki/Stoichiometry

11/27/2007 12:45:01 PM

^ 4 srs

11/27/2007 12:45:48 PM

o shit you're serious

11/27/2007 12:46:11 PM

yeah I don't speak chemistry

11/27/2007 12:49:10 PM

I did show my work. THAT'S ALL YOU NEED!

The atomic mass of Hydrogen is 1 amu (approx)
The atomic mass of Oxygen is 16 amu (approx)

Water is two hydrogens + 1 oxygen = 2 amu + 16 amu - (bond energy on the order of 1E-5 amu)
A mole of water is = 2 grams hydrogen + 16 grams oxygen

Notice there is 8 times as much oxygen mass as hydrogen mass. That's all you need to know to solve the problem. You can go to a periodic table and find that H is 1.00## amu and O is 15.996 amu to get a more accurate answer, but it doesn't change much.

The bold sentence is the entirety of the work you need to "show". Go through and multiply all the coefficients in the equation by the molecular masses:

4g H2 + 32g O2 -> 36g H20

11/27/2007 12:52:29 PM

btw if you still don't get it you should amputate your penis with a pocket knife. we wouldn't want you reproducing.

11/27/2007 12:54:33 PM

oh I get it

I'm not going to reproduce anyway, though

it would be an affront to God to produce offspring that may not understand chemistry
a working knowledge of basic chemistry is, after all, the cornerstone of civilization

11/27/2007 1:00:49 PM

convert grams to moles for everything

then use the 2:1 ratio

then convert from moles to grams for grams answers

^^true

Quote :

"I don't have a lot of experience with chemistry what with spending all of my time amongst the literature and philosophy departments"

didn't help much with practical aspects of reality did it?

while my answer is more 'technically correct' limpy's answer is right as well (difference only well past the . )

I really don't think that knowing how to think like this is exactly limited to chemistry, this is very very simple straightforward problem that blends 4th grade math with basic questions.

[Edited on November 27, 2007 at 1:07 PM. Reason : ]

11/27/2007 1:02:48 PM

^ If you look up the atomic masses on a periodic table and get the exact mass fractions, then my way yields EXACTLY the same answer as doing molar conversions. what you're proposing is like doing fourier transforms on an algebra problem. it adds a tremendous amount of work (more than doubling, possibly tripling the required computations), but it doesn't really do anything that you don't undo as well.

[Edited on November 27, 2007 at 2:35 PM. Reason : you should also probably refrain from reproduction.]

11/27/2007 2:34:01 PM

those are baby questions man

11/27/2007 2:35:56 PM

^^ exactly

transforms are supposed to make life easier, not harder

11/27/2007 2:37:16 PM

^^ no shit?

like I said, I'm not a scientist
I accept that I'm not "well rounded"

11/27/2007 5:53:37 PM

true limpy

11/27/2007 6:29:05 PM

I would've helped if I had seen this. Just for the record.

11/28/2007 12:11:39 AM

vanity search...

11/28/2007 12:13:11 AM

no, page 2 scan

[Edited on November 28, 2007 at 12:14 AM. Reason : .]

11/28/2007 12:13:54 AM

lies

11/28/2007 12:24:08 AM

for serious

because searching "Stillfuchsia" wouldn't be as profitable as "furshia" as far as titles are concerned

11/28/2007 12:25:29 AM