A gas is enclosed in a container at pressure P and absolute temperature T. If k is the Boltzmann constant, the number of gas molecules per unit volume is:

P/(kT)
kT/P
P/(RT)
RT/P

Correct answer: P/(kT)

Solution

From the ideal gas equation PV = NkT, the number density n = N/V = P/(kT), where k is Boltzmann constant and T is absolute temperature.

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