Thyroxine, the hormone, has the structure given below [figure] The percentage of iodine in thyroxine is %. (nearest integer) (Given molar mass in g mol-1 C : 12, H : 1, O : 16, N : 14, I : 127)
Answer
65
Solution
Counting atoms in the structure: 15 C, 11 H (4 aromatic H, OH, CH2, CH, NH2, COOH), 1 N, 4 O, 4 I
molecular formula C15H11NO4I4
Molar mass = 15(12) + 11(1) + 14 + 4(16) + 4(127)
= 180 + 11 + 14 + 64 + 508 = 777 g mol-1
% I = 508777 100 = 65.38\% 65\%
Answer: 65