unit 4.pdf can someone help me on 8b please
A2 AQA question helppp Watch
- Thread Starter
- 27-01-2010 00:07
- 27-01-2010 00:24
So you start with a solution of CO3 2- and HCO3- ions. The first lot of HCl converts CO3 2- ions into HCO3- ions, which you now have in addition to the HCO3- ions you originally had in your solution before any HCl was was added. Hence you need more HCl to then protonate all of the extra HCO3- you now have.
For the second bit, you first should find the total moles of HCO3- neutralised in stage 2 (remember 1 : 1 mole ratio of H+ : HCO3-). Once you have this, subtract the number of moles of HCO3- formed from stage 1, giving you only the number of moles of HCO3- you had right at the start. Then convert this number of moles into a concentration using the volume of 25 cm3 given to you for the solution. I got 0.0747 mol dm-3. See if you can get that.Last edited by Kyri; 27-01-2010 at 00:47.