# Questions tagged [ideal-gas]

For questions about the ideal gas law or gases which can be well approximated as an ideal gas.

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### How to convert molar volume to volume?

This seems like a simple question that people must have asked already, but I can't find an answer online. I'm not a chemist, but need to use a code that deals with thermodynamics. I am trying to use ...
1 vote
49 views

### Deviation from ideal gas behavior

I know that gases deviate from ideal behavior at low temperature and high pressure But what if we increase the pressure of a gas by increasing the temperature keeping the volume constant. Would the ...
72 views

### Is gas solubility independent of pressure?

My physical chemistry textbook poses this question: Prove the statement that an alternative way to express Henry’s law of gas solubility is to say that the volume of gas that dissolves in a fixed ...
57 views

### How can enthalpy of an ideal gas be independent of pressure?

I know that when one applies a manipulation of the Ideal Gas Law to the Maxwell Relations the result that enthalpy is independent of pressure tumbles out of it, i.e., (dH/dP) = 0. I don't understand ...
107 views

### When a gas is expanded, why doesn't the number of moles of a gas increase despite it's volume increasing (doubt in JEE sample question) [closed]

This question might be elementary, but it is genuine. I realise that some users might downvote the question for being so basic, but I urge them to be a little merciful, and help out a confused high ...
50 views

### Validity of ideal gas law for pure species or mixture

I'm currently dealing with an application involving gases. I have pure nitrogen as a pressurizer and eventually water vapour (only if condition for evaporation or boiling are met). I wanted to ask to ...
1 vote
233 views

### How do I determine temperature and pressure rise whenever mols of gases are added in a isolated room?

Let's consider a fully isolated room, no gas or heat flowing from it. We consider gases ($\ce{O2,N2,CO2}$) to follow the ideal gas law, and no chemical reaction occurs between them. Pressure $p$, ...
1 vote
93 views

### In collision theory why we multiply collision frequency by N/2?

In kinetic theory of gases we know that the average number of collisions, $N_\mathrm{col}$, is given by $$N_\mathrm{col} = \sqrt{2\pi\sigma^2 \overline{v}_\mathrm{rel}}\ N$$ where $N$ is the number ...
103 views

### RMS Speed of Gases as Standard Deviation

In kinetic molecular theory, the average velocity of gas particle is zero since the molecule move in different directions, and the overall effect is zero. Howeever, you can calculate different speeds. ...
342 views

### How do alpha particles contribute to pressure of nuclear decay products?

A closed vessel with rigid walls contains 1 mol of $_{92}\ce{U}^{238}$ and 1 mol of air at 298K. Considering complete decay of uranium to $_{82}\ce{Pb}^{206}$, the ratio of final pressure to initial ...
1 vote
107 views

### Is the change ΔG for an ideal gas unknown?

When one is introduced to the first law of thermodynamics, one learns that enthalpy is only a function of temperature, and calculating its changes is straightforward \begin{equation} \Delta H^\pu{...
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### According to PV=nRT,if we increase temp,no of moles will decrease,but no of moles is dependent on mass,mass is constant,then how can moles change?

We know the ideal gas equation is PV=nRT,then, according to this,if we keep Pressure,volume to be constant,then on increasing temperature,no of moles will reduce,this would mean that mass of matter or ...
1 vote
106 views

### How do I go about calculating final temperature of tank draining at saturation?

I am working on calculating pressure in a tank where the fluid is sitting at its vapor pressure. For example, imagine a 12 in diameter 100 L tank of nitrous oxide at room temperature (745 psi vapor ...
49 views

### How can Joule-Thomson inversion coefficient of ideal gas be zero? Does temperature of ideal gas not change on adiabatic expansion?

Does Joule-Thomson coefficient being zero means there will be no change in temperature? If that is the case then according to first law of thermodynamics, E = Q+W (don't know how to add delta sign). ...
56 views

### Calculating percentage of Zn in a coin

Question: An old coin found in an ancient temple is composed of zinc coated with copper. In an experiment to find the percent zinc in the coin, a student determined the weight of the coin to be 3.0 g. ...
277 views

### How exactly does Boyle's law, Charles' law, and Avogadro's law combine to make the Ideal Gas Law?

My General Chemistry 1 lecturer derived the ideal gas law as follows: We have $V \propto \frac1{P}$ (Boyle's law), $V \propto T$ (Charles' law), and $V \propto n$ (Avogadro's law). Combining these ...
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### Identify two hydrocarbons using volume and density [closed]

Question: A gaseous mixture with volume 16.8 dm3 contains two unsaturated neighboring hydrocarbons belonging to the same group. Density of the mixture was 14.4 times as hydrogen gas. What could be ...
271 views

### Find percentage of carbon monoxide reacted using ideal gas equation

Question A palladium or platinum catalyst was used in an automobile to convert carbon monoxide gas to carbon dioxide according to the following reaction: $$\ce{2CO(g) + O2(g) -> 2CO2(g)}$$ A ...
350 views

### My experiemental density of H2 does not match the published data. What causes this discrpenecy?

I placed 1 gram of NaBH4 in a balloon and placed it over a glass round bottle filled with water and acetic acid. While secured, I emptied the balloon into the bottle and made sure to wash the inside ...
194 views

### Dalton's law clarification

I'm looking at Elements of Physical Chemistry by Atkins and de Paula. In section 1A.3, they state Dalton's law as The pressure exerted by a mixture of perfect gases is the sum of the pressures that ...
84 views

### How to define percentage by volume for ideal gas and Why percentage by volume is equal to percentage by mole? [closed]

Why do we define percentage by volume for an ideal gas in a closed container in spite of that we know the ideal gas will occupy the volume of the whole container? I have seen many people who prove ...
101 views

### What is the Volume occupied by gas at extreme or limiting conditions of volume? [closed]

We know that 1 Mole of an Ideal Gas occupies 22.4 L at STP. [real gases also are also close to this volume , even tho there might be deviation, for this experiment let's take both to be same] But it'...
1 vote
83 views

### Henry’s Law Pressure Limitations

I’m trying to decide if I can I expect Henry’s Law to be an effective way to estimate how the solubility of a gas in a liquid solution will change if I decrease the pressure. I know Henry’s is best ...
213 views

### Can we calculate final temperature of two gases in thermal contact? [closed]

This is a question from IIT-JEE - ADVANCE 2018 A closed tank has two compartments A and B, both filled with oxygen (assumed to be ideal gas). The partition separating the two compartments is fixed ...
513 views

### Why do we subtract the volume correction term in the van der Waals gas equation [duplicate]

The following equation is valid for ideal gasses $$pV=nRT$$ Please mind the following notation, any parameter that is related to an ideal gas would be denoted with a subscript $i$ and anything related ...
1 vote
124 views

### Use the first law of thermodynamics to derive the pressure as a function of T, U, V and N

I am struggling with a thermodynamics question given $$S(U,V,N)=C_VNK_\mathrm b\ln U/U_0+NK_\mathrm b\ln V/V_0$$ (where $U_0$ and $V_0$ are the reference energies and volumes) and the first law of ...
232 views

### Molecular collisions in an ideal gas

(The equation of ideal gas is $pV=NRT$. If p = 1 atm, N = 1 mole, T = 0°K, and R = gas constant, then volume = V = zero. Hence, the volume of an individual molecule of ideal gas is zero). An ...
613 views

### Confusion in Van der Waals Equation

I understand that the behavior of ideal gases deviates largely from that of real gases in terms of pressure exerted by the gas molecules on the container in which it is present, space available for ...
284 views

### Gibbs Free Energy of Ideal Gas in Carnot Cycle

Let's just say we have 2 moles of monoatomic (maybe helium) ideal gas that is doing a Carnot Cycle with reservoir temperature of 300 and 750 K. Now, here's a simple question, what is the Gibb Free ...
1 vote
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### What is the necessary and sufficient condition for a mixture to be ideal?

I am trying to understand some concepts from solution thermodynamics related to ideal mixtures and fugacity. My main question is what is the necessary and sufficient condition for a mixture to be an ...
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### How do I calculate the temperature change in a gaseous reaction?

So, with $\pu{3 mol}$ of $\ce{H2}$ and $\pu{3 mol}$ of $\ce{Cl2}$ and given the reaction $\ce{H2(g) + Cl2(g) -> 2 HCl(g)}$ with $\Delta H=\pu{-184.6 kJ/mol}$, I am supposed to calculate the work ...
1 vote
251 views

### If Graham's law doesn't apply to the ammonia and hydrogen chloride diffusion in a glass tube demonstration, is there a law that does?

A comment below What exactly are "white fumes" and why does holding a bottle of ammonia (conc) next to a bottle of HCl (conc) make them? links to The Royal Society Of Chemistry video ...
227 views

### Why is Molar Mass of a gas twice the vapour density?

I've seen this relation at a number of places, and I can't get why. A simple Google search doesn't give me a simple answer either. Also, are there any exceptions/conditions for this relation to be ...