Calculate CO2 in atmosphere?

Question

I'm having trouble with this problem.

https://www.imsa.edu/admissions/cyberquiz/problem.php?qp_year=2008&qp_month=4&qp_grade=8

Could somebody direct me to a website or explain it in detail?

Thanks

Answer 1

If you know the surface pressure in PSI, or Pa, and you know the surface area of the planet you can calculate the mass of the atmosphere.  If you know the mass and the mass fraction that is CO2 you can work out the mass of CO2.

Just make sure units are consistent.....  pressure is in N/m^2 (or PSI) and you need to convert to kg/m^2 to find the mass..