Epinephrine (adrenaline) is a hormone secreted into the bloodstream in times of stress. It contains 59.0% C, 7.15% H, 26.20% O, and 7.65% N and has a molar mass of 183 g/mol. What is its molecular formula

C9H13O3N

Explanation:

Take the atomic mass of C=12.0, H=1.0, O=16.0 and N=14.0.

We can draw a chart (please view this on desktop so to avoid spacing errors):

Let the mass of Epinephrine be 100g.

                             C                       H                          O                              N

mass(g) :              59                      7.15                    26.2                         7.65

no. of moles : 59/12 =4.9167     7.15/1 = 7.15     26.2/16=1.6375 7.65/14=0.5464

(n.o.m. = mass/molar mass)

Ratio:   4.9167/0.5464 =9    7.15/0.5464=13      1.6375= 3      0.5464/0.5464 =1

(divide the n.o.m. by the smallest n.o.m., which is 0.5464 in this case, take the whole numbers)

So, the empirical formula will be: C9H13O3N

But this is still not yet the molecular formula. We have to ensure the molar mass is 183g/mol. Multiply the empirical formula by n.

So, let the molecular formula of Epinephrine be (C9H13O3N)n.

12x9n + 1x13n + 16x3n + 14n = 183

108n + 13n + 48n + 14n = 183

183 n = 183.

n = 1

Hence, the molecular formula is C9H13O3N.

every chemical equation adheres to the law of conservation of mass, which states that matter cannot be created or destroyed. therefore, there must be the same number of atoms of each element on each side of a chemical equation.