To solve this problem, let us first calculate for the number of moles of ghrelin in the blood. This is calculated by using the formula:
number of moles of ghrelin = Molarity * Volume of blood
number of moles of ghrelin = (1.3 × 10^-10 mol / L) * (1 L)
number of moles of ghrelin = 1.3 × 10^-10 mol
Avogadro’s number states that for every mol of a substance there is approximately 6.022 x 10^23 atoms or molecules of that substance. Therefore converting this into number of molecules:
number of molecules of ghrelin = 1.3 × 10^-10 mol (6.022 × 10^23 molecules / mol)
number of molecules of ghrelin = 7.8286 × 10^13 molecules