Calculating CO2 Concentration For Pepper Spray Devices

[mzuern]

TL;DR Summary

I have a kid who wants to do a report on aerosols.

I have a kid who wants to do a report on aerosols. As I understand, we have researched that for pepper spray devices liquid CO2 is used as a propellant, but we can't find out how they calculate the concentration. Is there a place we can find the right formulas needed?

 

[berkeman]

Summary:: I have a kid who wants to do a report on aerosols.

I have a kid who wants to do a report on aerosols. As I understand, we have researched that for pepper spray devices liquid CO2 is used as a propellant, but we can't find out how they calculate the concentration. Is there a place we can find the right formulas needed?

Welcome to PF.

It's unlikely that they referenced liquid CO2, since that requires very low temperatures and typically dewars are used for that, not spray cans

Please post links to the reading that you've been doing. Thanks.

 

[mzuern]

My mistake. It isn't liquid, but still how does someone determine how much is needed. Typically I think it only sprays for a maximum of 10 seconds. Is there a formula or ratio to determine amount needed?

 

[berkeman]

Please post links to the reading you've been doing about this. Thanks.

 

[Borek]

we can't find out how they calculate the concentration

Is there a formula or ratio to determine amount needed?

You seem to be using concentration and amount interchangeably - these are two different things, they mean different things and they can't be used freely one in place of the other (especially in the context of a school science project).

Please elaborate on what you want to find (and about the sources you consulted). It will really help us understand what you are looking for, right now we can only guess.

 

[hmmm27]

Liquid CO2 is pretty common at room temperature (and 80'ish bar IIRC) : that's the contents of the little tanks for seltzer bottles and some pellet guns ; it's the solid state that requires a low'ish temperature.

CO2 phase diagram

Maybe liquid nitrogen, which is used in spray cream, I think.