# Figuring % of H202



## jeneje (Feb 25, 2013)

Hey guys,

What im trying to figure out is how many ml i need to make a 15% solution of H202. I found some charts and after reading and converting I came up with this. The volume of my container is 1420ml - so to make the 15% solution out of 3% H202 i would need 501ml of H202 and 919ml of H20 = 1420ml total am i close here or way off. I am trying to learn the chemical math for the common chemicals we use. This is not easy to figure. Can someone recommend a book on this subject that would help me. I would be grateful. 

Thanks
Ken


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## bswartzwelder (Feb 26, 2013)

If you have 3% H2O2, to make it 15% you need to concentrate it, not dilute it. I don't know how to concentrate H2O2, but I doubt you can just boil it. Someone else who knows will be sure to help you.


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## kkmonte (Feb 26, 2013)

Hi Ken,

If you add just straight water to 3% H2O2, then you will get even less percentage. If you can get some other percentage of H2O2, i can show you how to do the math to figure out how to get to 15%, but you would need a higher percentage (around 30% H2O2).

Ken


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## jeneje (Feb 26, 2013)

kkmonte said:


> Hi Ken,
> 
> If you add just straight water to 3% H2O2, then you will get even less percentage. If you can get some other percentage of H2O2, i can show you how to do the math to figure out how to get to 15%, but you would need a higher percentage (around 30% H2O2).
> 
> Ken


Thanks kkmonte, i will call my supplier in the morning and see what they have or can get. I will send you a pm. i really need to understand how to figure this. Thank you very much.
Ken


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## philddreamer (Feb 26, 2013)

Go to a beauty supply store and buy some 40 volume peroxide. 3% is what you get at the drug stores; at the beauty supplys, 20 volume which is 6%; 30 volume is 9% and 40 volume is 12%. 
Phil


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## kkmonte (Feb 26, 2013)

The funny thing is I just helped a friend's daughter with her algebra and she had a question like this in the book.  Let me give you an example and you can just plug and play the numbers.

Let's say you have 3% H2O2 and you buy some 30% H2O2. How much of each would you need to make 1420 ML of a 15% solution.

X = amount of 3% solution you need
Y = amount of 30% solution you need

equation 1 (amounts): X+Y = 1420ml
equation 2 (concentrations): .03X+.30Y=.15(1420)

Solve equation 1 for one of the variables (ie Y) = Y = 1420-X
multiply equation 2 by 100 to make into whole numbers.

3X+30Y=15(1420)

substitute Y=1420-X into previous equation

3X + 30(1420-X) = 15(1420)
3X + 42600 - 30X = 21300
-27X = -21300
X = 788.9 ML

Y = 1420 - X
Y = 631.1 ML

Answer: 789ML of 3% and 631ML of 30% will give you 1420ML of 15%.


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## lazersteve (Feb 26, 2013)

You can get 35% Hydrogen Peroxide on ebay for about $25-35 a gallon.

Steve


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## etack (Feb 26, 2013)

kkmonte said:


> Let's say you have 3% H2O2 and you buy some 30% H2O2. How much of each would you need to make 1420 ML of a 15% solution.



why would you use two different concentration to confuse this. just use the 30% and add a 1:1 ratio of water.

some times "simple pictures are best". (good kids book) 8) 

Eric


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## jeneje (Feb 27, 2013)

Just got the call from my suppler, i can get 28%, 35%, and 50% H202. The cost is $100.00 for a case of 4 gallons. I am aware of the danger of 50% H202. I want to ues it to reduce the NOx to NO - what precent would i have to use? I am going to bubble the NOx through a two quart sealed container linked to another container of the same size with H2O linked to another container with H202 and then finialy into a bigger container fill with NaOH at a PH 10 to 14 before exiting into my hood and scrubber. 

Thanks
Ken


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## philddreamer (Feb 27, 2013)

> what precent would i have to use?


3%; you can use a higher percentage, but you should add water. Even 12% can burn your skin! Be careful!
Phil


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## jeneje (Feb 27, 2013)

philddreamer said:


> > what precent would i have to use?
> 
> 
> 3%; you can use a higher percentage, but you should add water. Even 12% can burn your skin! Be careful!
> Phil



Hey Phil, Thanks, That is good to know i did not know weather i should increase the % of H202. Cool i will just use standard over the counter.

Ken


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## Richard NL (Apr 29, 2013)

bswartzwelder said:


> Someone else who knows will be sure to help you.



If you want to concentrate the hydrogen peroxide.
Put the bottle in a sealed plastic bag in the fridge and label it hydrogen peroxide .
Label and plastic bag are for safety. 
Wait till it's a slush puppy or fully frozen and pour the concentrated h2o2 liquid out in a clean bottle.
What first comes out is the most concentrated hydrogen peroxide.
Use clean materials it's nasty stuff, and protect yourself.


I think it's better to freeze it then to warm it.

http://www.h2o2.com/technical-library/physical-chemical-properties/physical-properties/default.aspx?pid=22&name=Boiling-Points-and-Freezing-Points

But it is price technical better to buy the concentrate stuff, if you can get it.
This reply is also for all the other newbies.

Edit for clarity 1x.
Please correct me if I'm wrong or made a mistake, after 1 year i am still learning.


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