Explanation:
the morning of the birthday party balloon filled with the 2.5 Litre of helium
temperature is 294kelvin
the party starts at the 4 p.m.
temperature rises 305 Kelvin.
the new volume = 4 litre.
At same temperature,
P
1
V
2
=P
2
V
2
(Boyle's law)
P
1
=10atm;P
2
=1atm
V
1
=4l=V
2
=8l
But while filling balloons from cylinder when pressure in cylinder becomes 1 atm then further filling is not possible (P
1
′
=9atm)
Let n be the number of balloons that can be filled.
∴P
1
′
V
1
=n(P
1
V
1
)
9×8=n(4×1)
n=
4
9×8
=18balloons