A 10L cylinder has helium at 8 atm and `32^@C`. How many balloons of 2L each at 2atm and `32^@C` can be filled with the gas available from the cylinder.

Explanation

The PV of balloon `= 2 xx 2 = 4 lit-atm`
Gas from the cylinder is available to fill in the balloons, until its pressure drops from 8 atm to 2 atm.
The PV of helium available `= 10 xx (8 - 2) = 60` lit-atm
Number of balloons filled = `("PV of the gas available")/("PV of the balloon") = 60/4 = 15`