(Solved): 8.1 Composition of air. The approximate composition of dry air by volume at 20C is as follows: n ...

8.1 Composition of air. The approximate composition of dry air by volume at 20°C is as follows: nitrogen (N?) 78.09%, oxygen (O?) 20.95%, argon (Ar) 0.93%, and CO? 0.03%. 446 CHAPTER 8 Chemical Sensor and Actuators a. Calculate its composition by mass. Assume air is an ideal gas at an ambient pressure of 1 atm (101,325 Pa) and temperature of 20°C. b. Calculate the composition of air in mol/m³. The air density at 20°C and an ambient pressure of 1 atm is 1.2 kg/m³. c. Calculate the number of atoms (molecules in the case of CO?) per cubic meter (m³) of air for each constituent. Note: There are many other constituents in air, but the four included here are the most important in terms of quantities.