The amino acid lysine has the percent composition 49.3% C,9.59% H,19.2% N,and 21.9% O.If the molar mass is found to be 146 g/mol,what is the molecular formula of lysine?

Question

Quizplus · Accepted Answer

1) Calculate the number of moles of each element present in 146 g of lysine:
- C: (49.3 g / 12.01 g/mol) = 4.10 mol
- H: (9.59 g / 1.01 g/mol) = 9.50 mol
- N: (19.2 g / 14.01 g/mol) = 1.37 mol
- O: (21.9 g / 16.00 g/mol) = 1.37 mol
2) Divide all mole values by the smallest value to get the simplest whole-numbered ratio of atoms:
- C: 4.10 mol / 1.37 mol = 3.00
- H: 9.50 mol / 1.37 mol = 6.92
- N: 1.37 mol / 1.37 mol = 1.00
- O: 1.37 mol / 1.37 mol = 1.00
3) Round the ratios to the nearest whole number:
- C: 3
- H: 7
- N: 1
- O: 1
4) Write the molecular formula using the rounded ratios:
- C₆H₁₄N₂O₂, which simplifies to D.

The Amino Acid Lysine Has the Percent Composition 49