Question

To measure the volume of the blood system of an animal, the following experiment was done. A 1.0-mL sample of an aqueous solution containing tritium, with an activity of dps, was injected into the animal's bloodstream. After time was allowed for complete circulatory mixing, a 1.0-mL blood sample was withdrawn and found to have an activity of dps. What was the volume of the circulatory system

Answer 1

Answer:199mL

Explanation:

Let V ml be the volume of blood in animal.

When 1.0 ml sample is added, total volume becomes V+1.0ml. Its activity is 1000 dpm.

After equilibrium, 2.0 ml of the sample had activity of 10 dpm.

Hence, after equilibrium, the activity of V+1.0 ml of blood sample will be 10/2 (V+1.0ml)=1000dpm

Hence, V=199ml.