CO2 Pressure and density using PV=nRT?

Question

I did this calculation for a 12 gram CO2 cartridge and i know its not really the pressure inside of the CO2 it much to low, heres my question. I need to find the pressure inside a 12gram CO2 cartridge, i know the mass, n, t, and r, however i do not know V. What i did was use the mass and density to find V but density i used i believe is for STP which this is not. The 12 gram has CO2 gass inside no liquid does anyone know what the pressure inside the 12 gram is or which denisty to us to find it?

Answer 1

The gas inside those little 12 gram cartridges is pressurized to between 900 - 1000 psi.
If you look on a chart for CO2 the equilibrium pressure for CO2 gas at 80 Deg F is about 968 psi.
If you get these cartridges too cold, they can lose up to half their power.
See the following:

At 70 degrees F, CO2 obtains a gas pressure of 852.8 psi when confined in a vessel. If there is more CO2 in the vessel, it will be have to be in liquid form. So, the state of CO2 in a pressure vessel, such as a powerlet at room temperature, is a pressurized gas above a liquid. If the gas is released, such as through the operation of an airgun valve, some of the remaining liquid flashes to gas until the pressure is equalized for that temperature.

It's important to understand that CO2 pressure is determined by temperature, not by mechanical compression. If you were to compress gaseous CO2 by mechanical means, it would turn into liquid when the right pressure was reached. The pressure in a 12-gram powerlet remains constant until all the liquid is gone. A powerlet has the same internal pressure as a 10-oz. bulk CO2 tank when both are at the same temperature. Therefore, CO2 guns do not lose velocity as you shoot them until all the liquid is gone and they start to run out of gas.

Answer 2

I assume the cartridge is not in the 12 grams? You need the volume, so in a calibrated beaker of some type you fill it to a mark with water, immerse the cartridge in the water and read the new water level. The difference approximates the volume. You can estimate the cartridge itself and deduct it from the total. or weigh it and deduct the 12 grams to get the cartridge (empty) weight and calculate the cartridge volume using the density of steel.

or to get the volume, measure the cartridge and calculate it.

Answer 3

I may not be reading your problem correctly, which might be my problem. But when I read that you have a 12 gram CO2 cartidge that you have a cartidge that can up to hold 12 grams. Do you know the temperature this is at? If this was measured for standard temperature then you are golden. If not, there are tables in basic thermodynamic books that you can get a good library that list densities at different temperatures.

Answer 4

You could use P1V1 = P2V2. Get a cartridige and a balloon and see how big it gets from emptying the cartridge into it. The balloon will have to be big enough as not to have pressure greater than atmospheric.