Checagem de College Physics, 13.3 The Ideal Gas Law

The Ideal Gas Law: checagem

Problema e solução em inglês, como no livro original.

The density of air at standard conditions $(P = 1 atm$ and $T = 20 º C)$ is $1.28 {kg/m}^{3}$ . At what pressure is the density $0 . {64 kg/m}^{3}$ if the temperature and number of molecules are kept constant?

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Resposta
The best way to approach this question is to think about what is happening. If the density drops to half its original value and no molecules are lost, then the volume must double. If we look at the equation $PV = NkT$ , we see that when the temperature is constant, the pressure is inversely proportional to volume. Therefore, if the volume doubles, the pressure must drop to half its original value, and $P_{f} = 0 . 50 atm .$

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