Concentration of thyroxine (T4)= 120.4μg/L, Molecular weight = 777, Conentration in nmol/L=?

Question

it doesnt work out. i need to get an answer between 85-160nmol/l

Answer 1

okay first of all density = 120.4 * 10^-6 g/L

μ = micro corresponds to 10^-6

now density = mass/volume

Concentration = moles/volume

now since volume is not given you can solve for the volume in your concentration formula

volume = moles/concentration --> plug in to the density formula

density = mass/(moles/concentration)

so therefore

density = (mass * concentration)/moles

now you dont have moles or mass and moles = mass/Molar mass

so density = (mass * concentration)/ (mass/molar mass)

density = (mass * concentration) * Molar mass/mass

mass cancels out you are left with

density = concentration * Molar mass

(120.4 x 10^-6)/ (777)  =  concentration

The answer you get would be in mol/L

to n is nano so multiply your answer with 10^-9

Hope this helps