A student combusted an amino acid to try and figure out what amino acid she had.

Question

A student combusted an amino acid to try and figure out what amino acid she had. She knew he had a sulfur containing amino acid and that there were 5 carbons, 11 hydrogens and 1 nitrogen. Hence the formula is C_5 H_1.1 NO_2 S_n. Combustion of a 22.85 mg sample of the amino acid produced 9.810 mg of sulfur dioxide and 3.371 mg of dinitrogen oxide. What is the empirical formula of the amino acid? a. C_5 H_11 NO_2 S_1 b, C_5 H_11 NO_2 S_2 c C_5 H_11 NO_2 S_3 d, C_5 H_11 NO_2 S_4 For questions 25 --- 30 consider a fixed number of moles of unknown gas at a constant 31 degree C. In order to double the pressure in the system the volume will have to a. Increase by a factor of 2 b. Increase by a factor of 1.414 c. Decrease by a factor of 2 d. Decreased by a factor of 1.414 The reason the pressure changes in the question above is because: a. The gas particles begin to move more quickly. b. The average force of the collisions with the walls of the container changes c. The frequency of the collisions with the walls of the container changes d. Both the frequency and force of the collisions change If you allow the sample of unknown gas to expand to double its current volume, but that number of moles and temperature remain constant, the average velocity of the gas will a. Increase b. Decrease c. Stay the same d. You need to know the pressure of the system to answer this question. If helium diffuses twice as fast as the unknown gas above, the identity of the unknown gas might be: a. Hydrogen (H2) b. Neon (Ne) c. Methane (CH4) d. Argon (Ar)

Explanation / Answer

Ans 24 . a) C5H11NO2S1

Each mole of SO2 has 1 mole of sulfur

9.810 mg of SO2 has 4.90 mg of sulfur

22.85 mg of amino acid has 4.90 mg of sulfur

So that is (4.90/ 22.85) x 100 = 21.44 % by mass of sulfur in compound

Rest all other components make 78.56 % of the compound , having molar mass 117 g / mol

so the molar mass of sulfur in the compound = (21.44 x 117) / 78.56 = 32 g/mol

32g/mol = 1 mole of sulfur

so the compound formula is C5H11NO2S1

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

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