how do i calculate the percent by mass?

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einnelnnyl
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how do i calculate the percent by mass?

Post by einnelnnyl »

I want to determine the concentration of sodium carbonate and sodium hydrogen carbonate by titrating an unknown sample with HCl. I only have the mass of the sample and the volume of hcl used for titrating it with phenolphthalein and methyl orange. only with these data at hand, how will i be able to obtain the percent by weight?
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chempass
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Re: how do i calculate the percent by mass?

Post by chempass »

einnelnnyl wrote:I want to determine the concentration of sodium carbonate and sodium hydrogen carbonate by titrating an unknown sample with HCl. I only have the mass of the sample and the volume of hcl used for titrating it with phenolphthalein and methyl orange. only with these data at hand, how will i be able to obtain the percent by weight?
When you titrate with phenolphthalein only one reaction occurs:
Na2CO3 + HCl = NaHCO3 + NaCl
while with methyl orange two reaction occur:
Na2CO3 + 2HCl =H2O + CO2 + 2NaCl
NaHCO3 + HCl = H2O + CO2 + NaCl
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