Thermodynamic- Internal energy of dry air

AI Thread Summary
The discussion revolves around calculating the density and internal energy of dry air at specific conditions. For part (a), the user initially misapplies the ideal gas law but is corrected to use the formula p = P/RT, leading to a density of approximately 0.852 kg/m³. In part (b), the user seeks guidance on calculating the internal energy, which is defined as U = cvmT, where cv is the specific heat capacity at constant volume. The conversation emphasizes understanding the ideal gas properties and the correct application of thermodynamic equations. Overall, the thread highlights common challenges in thermodynamics homework related to ideal gas behavior.
harman12345
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Homework Statement


a) what is the density of dry air when the surface pressure is 1010hPa and the temperature is 27°C.

b) what is the internal energy of 1kg of dry air under these conditions?


Homework Equations


P=p*R*T where P is pressure and p is density.


The Attempt at a Solution


a) p = RT/P by solving it gives me
[287*(273+27)] / 101000 => 0.852kg/m

can someone please check what i did for part (a) is right or not?

b) i don't really get where to go with this question. So some help would be really appreciated thanks!
 
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harman12345 said:

Homework Equations


P=p*R*T where P is pressure and p is density.


The Attempt at a Solution


a) p = RT/P


Think it over...

ehild
 
ehild said:
Think it over...

ehild

OH my bad! should be p=P/RT right?

and hint for part b please
 
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