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98% of H2SO4 solution


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#1 sheanhung

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Posted 27 June 2006 - 10:00 AM

I have problem to determine the molarity of H2SO4 from 95%-98% H2SO4 solution with volume of 2.5 L stated on the bottle.

Besides, i am not sure what is the meaning of 95%-98%. Is this percentage is in term of volume, number of moles or weight of H2SO4?

If the molarity above is obtained, suppose i mix 1 volume this H2SO4 with 2 volume of water, what is the new molarity and number of moles of the diluted solution?

These problems are killing me. :confused: :confused: :-( Please help~!


*Are these informations useful?*
density of H2SO4 = 1.841 g/cm3
Molecular mass of H2SO4 = 98.08 g/mol
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#2 Primarygun

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Posted 27 June 2006 - 10:33 AM

98%

means that the H2SO4 has 98% of the total weight of a sample of H2SO4 solution.

In order to find out the molarity of the sulphuric acid,
there's a pretty good method.
Find out how many moles of H2SO4 are there in 1 dm^3 of water.
Then it is equal to the molarity of the acid.

what is the new molarity and number of moles of the diluted solution?

Molarity= no. of mole of a substance / volume of solution.
Since there's no departure of any H2SO4 molecules,
it follows that there exists the amount of H2SO4 molecules.
In this case , the molarity decreases as a result of the decrease in Volume of the solution
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#3 Borek

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Posted 28 June 2006 - 12:13 AM

Try these concentration lectures.
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#4 sheanhung

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Posted 28 June 2006 - 01:41 AM

Thank you. This website is useful!:-)
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#5 sheanhung

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Posted 28 June 2006 - 05:22 AM

I have calculated the molarity of the solution = 18 M

After dilution, the new molarity is roughly 6M. However, is this possible to use this diluted solution outside fume cupboard? What i understand is 6M is too concentrated to be used outside fume cupboard.

But, during my experiment, this diluted solution was placed on the bench only. Hmm......i think i have make mistake in calculation!
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#6 Primarygun

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Posted 28 June 2006 - 08:01 AM

But, during my experiment, this diluted solution was placed on the bench only. Hmm......i think i have make mistake in calculation

What does this mean?
You didn't use the diluted solution?
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#7 Darkblade48

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Posted 28 June 2006 - 01:10 PM

After dilution, the new molarity is roughly 6M. However, is this possible to use this diluted solution outside fume cupboard? What i understand is 6M is too concentrated to be used outside fume cupboard.

I suppose technically, you could use even an 18M solution of H2SO4 outside a fume hood, depending on the type of experiment you are using it for. Of course, it's not recommended, but not everyone has access to a fume hood.
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#8 sheanhung

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Posted 29 June 2006 - 01:41 PM

What does this mean?
You didn't use the diluted solution?


The H2SO4 put on the bench is diluted solution already. Diluted solution is made by mixing 1 volume of H2SO4 and 2 volume of H2O. (Eg. 5mL of H2SO4 + 10mL of H2O). The molarity of the diluted H2SO4 should be 6M if the formula MV = MV is applied. Am i correct?

If yes, is 6M of H2SO4 safe to use outside fume cupboard? (From mt knowledge, 6M is very concentrated too!)

:rolleyes:
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