How to Convert a Number Concentration into Volume Mixing Ratio?

[Geo_Zegarra2018]

Homework Statement

Convert a number concentration of 15 X 10^12 molecule/cm3 into volume mixing ratio at:

a) 1 atm pressure, and 20 C temperature.

b) 500 mbar pressure, and 253 K temperature.

Using the Ideal Gas Law, calculate:

a) Loshmidt’s number (# of molecules/cm3 of air, at standard atmospheric conditions “STP”, 1 atm pressure, and 273 K)

b) Density of atmosphere at “STP”

Homework Equations

The Attempt at a Solution

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I converted 15 x 10^12 molecule/cm^3 to mol/cm^3

 

[Borek]

How is the volume mixing ratio defined (I hate the way gases are treated in the atmosphere sciences, they define everything their own way just as if to make things incomprehensible to physicists and chemists )? What information do you need to directly apply this definition?

 

[Geo_Zegarra2018]

I honestly don’t know. Like if it told me what units to solve for I would probably have a better idea how to proceed this problem

 

[Borek]

Then you have to google for the definition or find it in your notes. That's your starting point.