# Determine pressure of flasks when opening stopcocks?

Three flasks with 1L of gas each are joined together with closed stopcocks. Flask A has a pressure of 5 atm, flask B has a pressure of 10 atm, and flask C has a pressure of 0 atm. How would I determine the new pressures when all flasks' stopcocks are open?

### 4 Answers

- Old Science GuyLv 75 months agoBest Answer
...

here's a quick common sense solution

suppose you open the connection between the 10 atm flask and the 0 atm flask

they would share and wind up at 5 atm each, of course

then connecting the other 5 atm flask would have no additional effect

so all 3 would be at 5 atm

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- electron1Lv 75 months ago
When the flasks' stopcocks are open, the volume of gas and the pressure in each flask will be equal. The total volume is three liters. The total pressure is 15 atmospheres.

Pressure = 15 ÷ 3 = 5 atm

I hope this is helpful for you.

- Roger the MoleLv 75 months ago
A weighted average does it:

((1 L × 5 atm) + (1 L × 10 atm) + (1 L × 0 atm)) / (1 L + 1 L + 1 L) = 5 atm

- Anonymous5 months ago
Assuming the pressures are absolute

( 1 L * 5 atm + 1 L * 10 atm + 1 L * 0 atm ) / 3 L = average pressure