blueberrynot
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Diluting H2SO2
I have some 96% concentrated H2SO2 (sulphuric acid) and want to dilute it to 5%. So how much water do I need to make 100ml of 5% concentration?
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elementcollector1
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H2SO4, you mean. Do you want 5% by weight or by volume?
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bfesser
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Doesn't matter, as long as it's the same as how 96% is measured.
.96 × .100 ÷ .05 =
We're not here to do your homework for you. Next time, put some effort into it before posting.
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woelen
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Thread Opened
29-10-2013 at 13:31 |
woelen
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I think it is not appropriate to close this thread. It is a beginner's question, perfectly placed in the beginner's section.
Besides that, your answer is not correct! Take into account the density of H2SO4. In fact, the answer to this question is not that trivial!
The density of 96% H2SO4 is appr. 1.836 g/ml at 20 C.
The density of 5% H2SO4 is appr. 1.032 g/ml at 20 C. A volume of 100 ml of this has a weight of 103.2 grams.
To make 100 ml of 5% H2SO4, you need 103.2 * 0.95 grams of water and you need 103.2 * 0.05 grams of H2SO4.
From the latter you can compute how many grams of H2SO4 you need and from that you can compute how many milliliters of 96% H2SO4 is needed (1 ml of
that acid contains 1.836*0.96 grams of H2SO4). These milliliters also add a little water (it is 96% H2SO4, not 100%, so one ml adds 1.836*0.04 grams
of water).
From the amount of needed water (assuming a density of 1.00 g/ml at 20 C) you need to subtract the little amount of water, coming with the H2SO4.
All these computations I leave for blueberrynot, but at least he has an outline of how such a computation can be done.
@elementcollector1: Volume percentages hardly make sense in this type of calculations, due to change of density and possible contraction or expansion
of mixes of liquids. In this kind of computations one works with mass percentages.
[Edited on 29-10-13 by woelen]
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elementcollector1
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@woelen: I agree, but I've ran into both before, and had to start asking due to the confusion.
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bfesser
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Quote: Originally posted by woelen  | | I think it is not appropriate to close this thread. It is a beginner's question, perfectly placed in the beginner's section. |
It's not a beginner's question, it's a lazy student asking us to solve his or her homework. Closing it was polite, compared to what
should have become of it. Even if (s)he isn't asking for homework solutions, it's a question that could have been answered by Google. The user has
no other posts, and has shown no sign of effort in answering the question. A zero-effort question gets a zero-effort (or intentionally incorrect)
response.
[edit] By the way, did you not even notice that this worthless excuse for a human being repeatedly typed "H2SO2" as the formula for sulfuric acid!?
It's a Beginnings section, not a Solve My Homework, Because I Can't Be Bothered section.
[Edited on 29.10.13 by bfesser]
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bismuthate
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We should have a lazy/stupid questions thread so we can send the lot of it to detritus every once and a while. The biggest mystery to me is why people
take 10 minutes to make an account and post instead of using google, or even *gasp* doing it themselves.
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