[imclair]

A white powder, consisting of a simple mixture of tartaric acid (C4H6O6) and citric acid (C6H8O7) was analysed to determine the elemental composition. Combustion of a 528.9-mg sample produced 644.2 mg of CO2 and 192.2 mg of H2O.

Use atomic masses: C 12.011; H 1.00794; O 15.9994.

It asks for
% of Carbon
% of Hydrogen
% of Oxygen
% of Tartaric Acid


I've found
% of Carbon = 33.24 %
% of hydrogen = 4.066 %
% of Oxygen = 62.69 %

But I don't know how i'm supposed to calculate the % tartaric acid, by mass, in the sample.

[Sleek]

A white powder, consisting of a simple mixture of tartaric acid (C4H6O6) and citric acid (C6H8O7) was analysed to determine the elemental composition. Combustion of a 528.9-mg sample produced 644.2 mg of CO2 and 192.2 mg of H2O.

Use atomic masses: C 12.011; H 1.00794; O 15.9994.

It asks for
% of Carbon
% of Hydrogen
% of Oxygen
% of Tartaric Acid


I've found
% of Carbon = 33.24 %
% of hydrogen = 4.066 %
% of Oxygen = 62.69 %

But I don't know how i'm supposed to calculate the % tartaric acid, by mass, in the sample.

i have a similar problem with different numbers though.. and im stuck on % tartaric acid as well..
i read somewhere that you have to add the % of C, H and O and the result should be 100 but it didnt work for me..

then i found this "x(% mass carbon in tartaric) + (1-x)(% mass carbon in citric acid) where x = is the fraction of tartaric acid. "

so far i got x*32% + (1-x)*37.5%
i have no idea what x is.. what's the fraction of tartaric acid?

[Borek]

moles of tartaric/(moles of tartaric + moles of citric)

[Sleek]

moles of tartaric/(moles of tartaric + moles of citric)

how can you find the moles of them? i can only find the molar mass..
150.088 / ( 150.088+192.124) = 0.43858

[S.V.]

moles of tartaric/(moles of tartaric + moles of citric)

how can you find the moles of them? i can only find the molar mass..
150.088 / ( 150.088+192.124) = 0.43858

You have the mass of CO₂ and H₂O produced. You have the mass of the powder mixture used. You can find their molar masses given the molar masses of carbon, hydrogen, and oxygen. Write the balanced chemical reaction. Look at mole ratios. I'm pretty sure this will work.