Looking for a function that returns the exactmass (monoisotopic mass) given a chemical formula in the following format:

c("C25H40N7O19P3S", "C25H40N7O19P3S", "C25H40N7O19P3S", "C25H40N7O19P3S" ,
"C9H12O4" ,       "C9H12O4",        "C9H12O4",        "C11H10N2O2",     "C8H16NO9P"   ,   "C8H16NO9P"    ,  "C8H16NO9P"  ,    "C8H16NO9P")

1. The mole allows scientists to calculate the number of elementary entities (usually atoms or molecules ) in a certain mass of a given substance. 2.Avogadro’s number is an absolute number: there are 6.022×1023 elementary entities in 1 mole. This can also be written as 6.022×1023 mol-1.
   1. The mass of one mole of a substance is equal to that substance’s molecular weight. For example, the mean molecular weight of water is 18.015 atomic mass units (amu), so one mole of water weight 18.015 grams.
   2. Key Terms mole: The amount of substance of a system that contains as many elementary entities as there are atoms in 12 g of carbon-12.

Team: groomyourcar