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# Concentration Calc Help

1. Can anyone help, how do i find the undiluted concentration of H2SO4, 100cm3 was diluted with water to make a 1.00 dm3 solution.

I know from my previous calc that the concentration of the diluted H2SO4 was 0.625 moldm3 (moles 0.0125 / vol 0.02 dm3)

but am struggling with the last bit
2. (Original post by redfoo12)
Can anyone help, how do i find the undiluted concentration of H2SO4, 100cm3 was diluted with water to make a 1.00 dm3 solution.

I know from my previous calc that the concentration of the diluted H2SO4 was 0.625 moldm3 (moles 0.0125 / vol 0.02 dm3)

but am struggling with the last bit
Your initial dilution was from 100 to 1000ml

This is a 10 fold (x10) dilution.

This makes a concentration ten times more dilute.

Hence the original solution was ten times more concentrated.
3. (Original post by charco)
Your initial dilution was from 100 to 1000ml

This is a 10 fold (x10) dilution.

This makes a concentration ten times more dilute.

Hence the original solution was ten times more concentrated.
so if concentration of 0.02dm3 diluted was 0.625 moldm3 then the 100 would be 10 x 0.625 = 6.25 moldm3 conc

is that correct
4. (Original post by redfoo12)
so if concentration of 0.02dm3 diluted was 0.625 moldm3 then the 100 would be 10 x 0.625 = 6.25 moldm3 conc

is that correct
If I understand you correctly...

You dilute a stock solution by a factor of 10

Then you test the concentration of a 20ml sample which turns out to be = 0.625 M

If so, yes.

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