Vitamin K antagonists (VKA) are a group of substances that reduce blood clotting by reducing the action of vitamin K. They are used as anticoagulant medications in the prevention of thrombosis, and in pest control, as rodenticides. 1  1 Mechanism of action.  2 Coumarins (4-hydroxycoumarins)
Calculate the average atomic mass of oxygen. Solution: ((15.994915*99.757) + (16.999132*0.038) + (17.999160*0.205))/100 = 15.999405 . Using our equation for determining average atomic mass, we see that the average atomic mass for oxygen is 15.999405 amu. If we check the periodic table, we will see that our average atomic mass is the same as the atomic mass indicated on the element oxygen. Ã
The atomic mass of carbon is 12.011. Most carbon atoms consist of 6 protons and 6 neutrons. The atomic mass of hydrogen is 1.0079. Hydrogen (atomic number 1) is the element that has the lowest atomic mass. The most common isotope of hydrogen is protium, an atom that consists of a proton or a proton and an electron.