- #1

roam

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## Homework Statement

A spherical balloon is filled with helium atoms (Note 1 atm = 101.3 kPa).

**(i)**What is the total translational KE of the atoms if the balloon has a diameter 13.0 cm at 37.0 °C and the pressure inside the balloon is 121.6 kPa?

**(ii)**The above balloon was filled from a cylinder of volume 0.2 m3 containing helium gas of 190.0 atm and at the same temperature as in the balloon in (i). How many of the balloons in (i) can the cylinder inflate?

## The Attempt at a Solution

**(i)**To find the translational kenetic energy I think I need to use the equation

[tex]\frac{2}{3} nRT[/tex]

But the problem is that the number of moles is not given to us. I tried finding it using the formula n=m/M, but that won't work because I know that the molar mass of helium is 4 g/mol but I don't know what the mass (m) is!

T=37.0 °C + 273.15 = 310.15 K

[tex]\frac{2}{3} n(8.314)(310.15)[/tex]

I can't go any further.

Any help is appreciated.