The Rate of Oxygen Absorption by the Lungs: An Elementary Chemistry Laboratory Experiment for Biology-Oriented Students A standard laboratory experiment for determining the percent oxygen in the air by the white phosphorus/eudiomet'er tube method1 can he extended into a project of greater interest to elementary chemistry students planning careers in biology or the applied biological sciences. The rate of oxygen absorption by the lungs may he followed by using ordinary rubber balloons to collect samples of air held in the lungs of a subject for varying lengths of time and then transferring the samples to eudiometer tubes for oxygen analysis. Plotting the logarithm of the partial pressure of oxygen versus time yields a reasonable straight line; the slope of the line may be used to calculate a n apparent first-order rate constant2 for oxygen absorption by the lungs, and the yintercept is the logarithm of the normal oxygen partial pressure in air. Attempts can he made to correlate rate constants from several subjects with factors such as age, weight, smoking status, health and state of repose. Students are amused when asked to design an experiment for determining the activation energy for the oxygen absorption process. A bonus in this project is the "fireworks" display which results when small amounts of waste phosphorus are disposed of by warming in a crucible in a closed hood. 'Metcalf, H. Clarke, Williams, John E., and Castko, Joseph F., "Exercises and Experiments in Chemistry," Holt, Reinhart and Winston, Inc., New York, 1970, p. 169. 2Values typically fell in the range 0.14 min-'-0.18 min-1. Person to whom all correspondence should he directed. Donald R. GetzinS Wayne Wysoczynski
The Newark College of Engineering Newark, New Jersey 07102
414
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Journal of Chemical Education
