# Questions tagged [ideal-gas]

A gas that behaves as randomly moving, non-interacting molecules. This allows a simplified equation of state.

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### What is the reason of $dT/dh = 0$ in the gas column?

According to thermodynamics every adiabatic system and (with no external energy added) will reach thermodynamic equilibrium or an ergodic state (2 law of thermodynamics entropy can not decrease in a ...
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### What's the difference between $pv=RT$ and $pV=nRT$?

I know this will sound dumb for the people who are here but I need to learn eventually when can I use $pv=RT$ and when to use $pV=nRT$
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### Density of ideal gas molecules

From Boyle's Law, in very low pressure ($P \rightarrow 0$), it is a good approximation for real gases to behave as ideal gases. (refer to the graph) Boyle's Law stated that $P \propto \frac{1}{V}$ ...
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### What is the difference between a macrostate and multiplicity?

The entropy of a system of an ideal gas depends on the external parameters $U, V, N$. I always thought entropy is defined by a certain macrostate, which is a set of given external conditions like ...
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### Does the ideal gas law apply to gases which consist of more than one atom?

In the derivation of the ideal gas law, one sets for the average kinetical energy $f = 3$ degrees of freedom. This refers to the transition in x,y,z axes. This is true for gases, which consist of only ...
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### Given pressure in Pascals and temp in Kelvin what equation determines the weight of a volume of air? [closed]

I'm trying to determine how many kg of air that a Zeppelin displaces. The volume of the airship is 58142.1 meters cubed. The temperature of the air is 276.26 kelvin. The pressure in pascals is 42,178....
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### Temperature change of an ideal gas during an adiabatic free expansion

During an adiabatic process there is no heat exchange and thus, q = o. During a free expansion no work is done and so w = o. Since q = U + w, thus we can say that during the overall process, change in ...
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### For a gas in an open vessel, should the volume of gas be the volume of whole universe?

In the ideal gas equation $PV=nRT$, $V$ is defined as free space available to the gas. In an open vessel in which temperature is maintained constant, shouldn't the volume $V$ of the gas be the volume ...
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### Work done "by gas" in a isobaric process?

Starting from First Law of Thermodynamics, we have ΔQ = ΔU + ΔW Where, ΔW is the work done "by gas" on the surrounding. Now, for an isobaric process, it is given by ΔW = ∫PdV = PΔV here ...
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### What exactly is the use of partial pressure of a component?

Is partial pressure the actual pressure a component contributes in a mixture? What is the physical essence of partial pressure?
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### Why is volume of a gas in an open container assumed to be constant?

I've read this in a book When air is heated in an open vessel, pressure is always atmospheric pressure, and volume of the gas is constant. How is volume of the gas constant in this case?
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