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
1 For glucose, C 6 H 12 O 6, the molar mass of each element is 12.0107 times 6, or 72.0642 grams per mole for carbon; 1.007 times 12, or 12.084 grams per mole for hydrogen; and 15.9994 times 6, or 95.9964 grams per mole for oxygen.