# chemistry help on concentration

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#1
50cm3 of sodium hydroxide solution added to a solution of sulfuric acid. The concentration of the sodium hydroxide solution was 20g/dm3. Work out the concentration of the sulfuric acid in grams per dm3 if it took 25cm3 of it to completely neutralise the sodium hydroxide. The relative molecular mass of sulfuric acid is 98.
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1 month ago
#2
(Original post by Snigdha02)
50cm3 of sodium hydroxide solution added to a solution of sulfuric acid. The concentration of the sodium hydroxide solution was 20g/dm3. Work out the concentration of the sulfuric acid in grams per dm3 if it took 25cm3 of it to completely neutralise the sodium hydroxide. The relative molecular mass of sulfuric acid is 98.
What have you tried to do with the numbers you've given to us?
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#3
I've found the mass of sodium hydroxide by using the concentration is mass over volume. That got me 1g. Then I found the moles of sodium hydroxide by doing mass over RAM which got me 0.025mol. But that already seems wrong
Ive also written a balanced equation:
2NaOH + H2SO4 = Na2SO4 = Na2SO4 + 2H2O
Using that I worked out that the sulfuric acid is half the amount of moles sodium hydroxide is so it's 0.025 divided by 2 to get 0.0125mol and then I times that by 98 which is sulfuric acids ram to got 1.225 as the mass
then i replaced that mass into the concentration equation so i times the 1.225 with 25 and i got 0.049dm cubed but for some reason the answer is actually 49
I would appreciate any help
Last edited by Snigdha02; 1 month ago
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#4
oop i've just realised where i went wrong
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#5
thank you for your help though.
I guess you just need to talk it through to find your mistake
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