Read everything befor answering. I have asked some very specific questions and t

Question

Read everything befor answering. I have asked some very specific questions and the last person to help me with this did not answer the question.


2.Calculate the number of moles of sodium carbonate present in a mixture of sodium bicarbonate, sodium carbonate and a neutral component if 6.0 ml of 0.100 M HCl were used to titrate 0.200 g of this mixture with phenolphthalein as the indicator.

4. Calculate the number of moles of sodium bicarbonate originally present in the unknown mixture in question 2, knowing that 15.0ml of 0.100 M HCl were used in step 2 of the titration, Using methyl orange as the indicator.

I allready calculated the Molar Masses: HCl= 36.460g, Na2Co3 = 105.99g, and NaHCO3 = 84.007g

I am completly confused on these two questions and even though I have a template (quantity/MM)(Molar ration of balanced equation/wanted)(MM of wanted substance/1 mol of such) for question #2, Me and the tutor at my school could not figure these problems out.

Please show me a step by step process so that I can figure out what I am doing wrong for each question. "Do not give me a template to follow"

Thank you

Explanation / Answer

I will answer part 4 separately if you post it as another question. Thanks

2.This first part of the problem deals with the first part of the titration. As such, the stronger base, sodium carbonate, reacts first to the first endpoint. There are 2 endpoints in the titration of diprotic acids and bases. It is indicated by phenolphthalein, since the solution is expected to be basic at the endpoint, with all of the base present as bicarbonate ion and none as carbonate.

0.006L * 0.1 mole/L acid = moles of sodium carbonate present = 6*10-4 moles of sodium carbonate present

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