The concentration of oxygen leaving an oxygen concentrator depends on the:

a. number of sieves in the unit.
b. number of compressors used.
c. set flow rate of the gas exiting.
d. size of the sodium-aluminum silicate pel-lets.

ANS: C
Atmospheric gases diffuse through the membrane at different rates. The rate at which a gas dif-fuses depends on its diffusion constant and solubility for the plastic membrane and the pressure gradient for the gas across the membrane.