Question

A small cylinder of helium gas used for filling balloons has a volume of 2.50 L and a pressure of 137 atm at 25 degrees Celcius. How many 1.50 L balloons can be filled if the internal pressure of each balloon is 1.25 atm at 25 degrees Celcius?

Answer 1

volume of ballons = 2.5 L

pressure = 137 atm

temperature = 25 C = 298 K

PV = nRT

137 x 2.5 = n x 0.0821 x 298

n =14

V= 1.5 L, P = 1.25 atm , T = 298 K

PV = nRT

1.25 x 1.5 = n x 0.0821 x 298

n = 0.0767

now

number of ballons filled = total number of moles / each ballon moles

                                     = 14 / 0.0767

                                     = 182.5

number of ballons filled = 182.5