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
oxygen consumption the amount of oxygen consumed by the tissues of the body, usually measured as the oxygen uptake in the lung. The normal value is 250 ml/min (or 3.5 to 4.0 ml/kg/min), and it increases with increased metabolic rate. chemical element, atomic number 8, atomic weight 15.999. (See Appendix 6.) It is a colorless and odorless gas that makes up about 20 per cent of the atmosphere. In combination with hydrogen, it forms water; by weight, 90 per cent of water is oxygen. It is the third most abundant of all the elements of nature.