What is the mass of the helium present - Thermodynamics

cmilho10
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A sample of helium behaves as an ideal gas as energy is added by heat at constant pressure from 273 K to 383 K. If the gas does 23.0 J of work, what is the mass of helium present?

I tried this and think u use m=Q/c*change in T, but not sure where to go from there
 
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The expression for the work done by the gas is:
dW=PdV
Since there is constan pressure we can write:
V=\frac{nRT}{P}
dV=\frac{nR}{P}dT
So
dW=nRdT
and
[/tex]W=\int_{T_1}^{T_2}nRdT[/tex]
Do the integral, use the molar mass of He to convert the # of moles of He to the mass, and then solve for the mass.
 
To solve this, I first used the units to work out that a= m* a/m, i.e. t=z/λ. This would allow you to determine the time duration within an interval section by section and then add this to the previous ones to obtain the age of the respective layer. However, this would require a constant thickness per year for each interval. However, since this is most likely not the case, my next consideration was that the age must be the integral of a 1/λ(z) function, which I cannot model.
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