Answer to Question #312858 in Chemistry for jane

Question

The amino acid methionine, which is essential in human diets, has the molecular formula C5H11NO2S. Determine (a) its molecular mass; (b) the number of moles of H atoms per mole of methionine; (c) number of grams of C per mole of methionine; (d) the number of C atoms in 9.07 mol methionine

Answer 1

Solution:

(a):

Calculate the molecular mass of methionine (C₅H₁₁NO₂S):

M_r(C₅H₁₁NO₂S) = 5×A_r(C) + 11×A_r(H) + A_r(N) + 2×A_r(O) + A_r(S)

M_r(C₅H₁₁NO₂S) = 5×12.0107 + 11×1.00784 + 14.0067 + 2×15.999 + 32.065 = 149.209 = 149.21

The molecular mass of methionine is 149.21 g/mol

(b):

Calculate the number of moles of H atoms per mole of methionine:

C₅H₁₁NO₂S → 11H

Thus, 1 mol of methionine contains 11 mol of H atoms

11 moles of H atoms per mole of methionine

(c):

Calculate the number of grams of C per mole of methionine:

C₅H₁₁NO₂S → 5C

Thus, 1 mol of methionine contains 5 mol of C atoms

The molar mass of carbon (C) is 12.0107 g/mol

Therefore,

Mass of C = (5 mol C) × (12.0107 g C / 1 mol C) = 60.0535 g C = 60.05 g C

60.05 grams of C per mole of methionine

(d):

Calculate the number of C atoms in 9.07 mol methionine

1 mol of methionine contains 5 mol of C atoms

Thus, 9.07 mol of methionine contains 5×9.07 = 45.35 mol of C atoms

One mole of any substance contains 6.022×10²³ particles

Therefore,

Number of C atoms = (45.35 mol) × (6.022×10²³ atoms / 1 mol) = 2.73×10²⁵ atoms

2.73×10²⁵ carbon atoms in 9.07 mol methionine