Friday
May 6, 2016

# Homework Help: lab

Posted by Melba on Monday, September 25, 2006 at 7:28pm.

Number of moles of oxygen gas produced from the complete catalyzed decomposition of 6.80ml sample of a 3.5% solution. Density of the 3.5% solution of H2O2 is 1.01g/ml

Let's find out what you know about this and work from there. Show your calculations to the point that you are stuck; otherwise, I may repeat much of what you already understand.

d = m/v
1.01=m/6.80 ml
m=6.868gr
coefficients of reaction: 2,2,1
two moles of H2O2 produce 1 mole of O2(g)
then 6.868gr of H202 should produce...?
I try .1009524929 and .2019049859 but they are not the right values...help...I am stuck...

Thank you for posting your work. The 6.868 g is correct. BUT that is only 3.5% H2O2; therefore,
6.868 x 0.035 = xx g H2O2
mols H2O2 then is xxg/molar mass H2O2.
mols O2 = 1/2 mols H2O2. Then I would round the number to two significant figures (since 3.5% has only two UNLESS you just left the zero off and the original problem was 3.50% H2O2).
I hope this helps.

BIG Help!!!!
Thanks....