A2 Chemistry
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I am doing a back titration calculation, I need to make up 0.1M HCl from 1M HCl, but do not know how much water is needed?
What volume of water is required to make 250 cm3 of 0.1M HCl from 1M of HCl?
010208
Corrie writes ....
You don't need to know the volume of water. The way to dilute a solution accurately by a factor of 10 is to use a volumetric flask (the ones with the long narrow neck with a volume mark on it) with a volume equal to the volume of diluted solution you want - in your case 250 cm3. Measure out (pipette?) a tenth of this volume (in your case 25 cm3) of the 1M acid into the volumetric flask, then fill it up to the mark with water. Shake well!
If you are not too worried about the accuracy you could do the dilution in a 250 cm3 measuring cylinder instead. Measure 25 cm3 of the 1M acid into it and then fill it with water to the 250 cm3 mark. Again, mix well!
As you can see the volume of water needed to dilute 25 cm3 1M acid to 0.1M is 225 cm3, but you don't need to measure it out separately!
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updated: 01 February 2008
