A white powder, consisting of a simple mixture of tartaric acid (C 4 H 6 O 6 ) a

Question

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 495.3-mg sample produced 610.5 mg of CO2 and 180.6 mg of H2O.

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

1) Calculate the % hydrogen, by mass, in the sample.

2) Calculate the % oxygen, by mass, in the sample

3)Calculate the % citric acid, by mass, in the sample.

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

1) Calculate the % hydrogen, by mass, in the sample.

2) Calculate the % oxygen, by mass, in the sample

3)Calculate the % citric acid, by mass, in the sample.

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 495.3-mg sample produced 610.5 mg of CO2 and 180.6 mg of H2O.

Explanation / Answer

Solution :-

Lets calculate the moles of the mass of of the C and H using the percent of the C and H in CO2 and H2O

Mass of C = (610.5 mg CO2 *27.29 % C / 100 %)*(1000 mg/1 g) = 166.6 mg C

Mass of H = (180.6 mg H2O *11.19 % H / 100 %) = 20.21 mg H

Now lets calculate the mass of oxygen

Mass of O = total mass – (mass of C+ mass of H)

                    = 495.3 mg – (166.6 mg + 20.21 mg)

                    = 308.49 mg O

Now lets calculate the percent of the H and O

% H= (mass of H / total mass )*100%

      = (20.21 mg/495.3 mg)*100%

     = 4.08 %

% O = (mass of O / total mass) *100%

        = (308.49 mg/ 495.3mg)*100%

     = 62.28 %

Both citric acid and tartaric acid contains total 6+8 = 14 mol H

lets calculate the percent of the H that comes from citric acid

(6/14)*100% = 42.85 %

So the citric acid is 42.85 %

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.