# Confused - Pressure in a canister???

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1. Jul 15, 2015

### b.kiddo44

A manufacturer quotes a standard co2 canister contains 16g of co2 at a volume of 20cm^3.

So I need to calculate the pressure in the canister....

Using ideal gas law

P = nRT/V
n = 0.364mol (16 of co2)
R = 8.314 J/Kmol (universal gas constant)
T = 294k (gas is at room temp 21 deg C)
V = 20cm3 (volume of canister as quoted)

P = 444 Bar

However the manufacturer quotes the canister pressure to be 60Bar! This seems a bit more realistic to me but I've no idea how this could be the case.

Any thoughts to clear up the confusion?

2. Jul 15, 2015

### RyanH42

Its must be cubic meter.Convert 20 cm3 to meter3

3. Jul 15, 2015

### b.kiddo44

Good point, but I already did the conversion to m^3 in the calculation to give 444Bar.

4. Jul 15, 2015

### RyanH42

I dont know chemical very well but maybe theres another formula to calculate pressure.Maybe CO2 supposed to be non-idel gas.

5. Jul 15, 2015

### b.kiddo44

hum, I don't think it matters if the gas is 'ideal' or not. The manufacturer quoting 16g of co2 in a 20cm^3 canister stored at room temperature. I'm confused as to where the 60 Bar quote comes from.

6. Jul 15, 2015

### Dr. Courtney

Perhaps the CO2 is not all a gas under pressure and the pressure is the vapor pressure at a given temperature.

7. Jul 15, 2015

### RyanH42

You wrote it isnt it ?

8. Jul 15, 2015

### RyanH42

Theres only two option.First option this is not an idel gas.Ideal gas make the equation simpler but maybe theres another type of equation which I said before.
Second think As you said its not 60 bar

Theres no other option cause our solution is correct.

9. Jul 15, 2015