Thursday
May 5, 2016

# Homework Help: help with stochiometry

Posted by iearn on Wednesday, January 24, 2007 at 11:03am.

can someone help me out with this one? balanced equation is:
2H2 + O2 > 2H2O
My questions are:
How many molecules of water are produced from 2.0 * 10 ^23 molecules of oxygen?
How many moles of water are produced from 22.5 moles of oxygen?

OK. First, it depends on if you really mean molecules or if it is moles. I'm guessing you put molecules because that is what's on your sheet, so we'll go with that.

First you must convert molecules to moles of oxygen. I used "parts" instead of "molecules" just because the word is smaller.
(2*10^23 parts)(1 mol O2/6.022*10^23 parts)=0.332 moles O2
Now you can cross out the "parts" in the top and bottom. Then you need to compare moles of O2 to H2O:
(0.332 moles O2)(2 moles H2O/1 mol O2)=0.664 moles H2O
I got the moles of water over oxygen from the original balanced equation. Now, convert the moles of H20 to molecules of H20:
(0.664 moles H2O)(6.022*10^23 parts/1 mol H2O)=4*10^23 molecules of water.

For the next question, try it yourself and show your work on here and I'll let you know if you get it right.

IS THIS CORRECT:
22.5*1MOL O2/6.022*10^23 = .0037

.0037*2=.0074

Look at the equation.
1 mol O2 produces 2 mols H2O.
22.5 mols O2 will produce ????mols H2O?

22.5 ?

would I just multiply 22.5 * 16.00?