Our Task Is to Measure the Volume of Blood in an Elephant

Multiple Choice

Our task is to measure the volume of blood in an elephant. One way to do this would be to drain its blood into a suitable container. Aside from harmful side effects which this method has on the elephant, it will not be successful, as blood will still remain behind in the tissues. Hence, we will inject 2.00 ml of a 2.00 M solution of a dye which the elephant will not appreciably metabolize or excrete in one hour and then measure the concentration of this dye in the bloodstream (our sample being taken from another leg than the point of injection) after 30 minutes, a sufficient time to thoroughly mix the dye in the bloodstream. The concentration of dye at this point is 1.25 x 10^-5 M. What is the volume of blood in the elephant?

A) 320. L
B) 320000 L
C) 3.2 L
D) 80 L
E) 800 L