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Questions tagged [gas-laws]

Physical and chemical laws describing the properties and behavior of gases. This tag currently applies to properties and laws concerning both ideal and real gases.

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How can I identify a gas that has a larger density than another gas that was given a volme ratio [on hold]

Air is a mixture of N2 and O2 which the volume ratio is 4 : 1. How can we know that C3H8 has a larger density? I do not know how to start resolving this problem, The one that I know is the molecular ...
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24 views

Total pressure of mixture

I have the following problem: We put 200 mL of an equimolar mixture of pentane and hexane in a 900 mL container at a temperature of 20 °C. While the container is sealed, dry air at atmospheric ...
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50 views

What Does R' Mean in this Equation?

In equation 3-16, there's a R' that appears which doesn't get explained in the proceeding paragraph. I see R in the equation before the final equation is the gas constant, but there's no explanation ...
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0answers
18 views

Heating different ideal gases in separate containers

Let's say that three different gases (e.g. $\ce{Ar, O2, H2O}$) are placed in separate containers. A fixed amount of energy is deposited by heat transfer into each gas. Assuming ideal gas behavior, how ...
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1answer
29 views

How does a gas occupy a fixed molar volume?

It is common knowledge that one mole of ideal gas occupies a volume of 22.41 L at standard temperature and pressure (0°C and 1 atm). However, this goes against the claim that gases don't have a fixed ...
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1answer
19 views

Why is STP mol/liter so specific? [duplicate]

How do we know that one mole of an ideal gas occupies (exactly) 22.4 Liters? Why is it so precise a value? Many other constants/conversions in science have multiple decimal places, so why is this ...
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2answers
58 views

Why do Gas Laws only use Kelvin Temperature? [closed]

I didn't see this in any other question, although it seems to be a fundamental question of the gas laws. I understand that Charles' Law practically has to use Kelvin temperature, because you would end ...
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1answer
25 views

What does the volume of a gas depend on?

In my chemistry textbook, it states that the volume of a gas is directly proportional with the amount(number of moles) of that gas. However, it also mentioned before that the volume of a gas depends ...
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1answer
105 views

If temperature and volume are same, the pressure of gas obeying van der Waal's equation is smaller than that of an ideal gas"

Can you state the reasons for it. I think " It is smaller because mutual forces of attraction would resist the collision of particle and container".
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1answer
73 views

Can ideal gas law be applied to water vapour? [closed]

How to accurately estimate the molar concentration of pure water vapour at 298 K? Can ideal gas law be applied to water vapour to calculate the molar concentration?
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2answers
62 views

What's wrong with this gas law problem?

I recently took a chemistry test in which the following problem was offered: a 137 mL gas sample is collected over $H_2O$ at 753 mmHg and $22^oC$. What is the volume of the dry gas at STP if the ...
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36 views

Feasibility of application of Boyle's law in the case of varying number of moles [closed]

While reading up on ideal gases and the Boyle's law, I encountered a question in my textbook wherein a balloon was being filled with helium (assumed to be ideal) till it was just about to burst. The ...
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1answer
27 views

Equalizing Pressure Question

I have a question about the gas collection over water lab: We learned that when the water level inside the graduated cylinder is higher than the outside water level, the gases inside the graduated ...
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1answer
55 views

Calorific value of a gas in combustion

The Wikipedia article on heat of combustion says: The calorific value [...] may be expressed with the quantities: energy/mole of fuel energy/mass of fuel energy/volume of the fuel ...
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0answers
46 views

Comparing pressure and volumes of ideal and real gas

This question has been troubling me for quite a while now. Which has greater pressure: Real gas or an ideal gas under similar conditions? What about their volumes? I read this in many sources and ...
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1answer
84 views

Why do gases coexist as liquid and vapour?

I have having difficulty in understanding the liquefaction of gases.In the graph of isotherms of $\ce{CO2}$ I cannot understand how can gas coexist as liquid and vapour under area of $\mathrm{XCEBY}$....
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1answer
41 views

Why are moles used in the ideal gas law and not simply mass?

The crux of my question is, why is just the amount of particles included in $PV=nRT$ and there is nothing to account for the mass of the individual molecules? Or is mass accounted for in temperature, ...
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1answer
49 views

Interpreting straight lines in a graph of isotherms of carbon dioxide

I am having difficulty in understanding pressure-volume graphs of $\ce{CO2}$ at different temperatures which describes liquefaction of $\ce{CO2}$. I know that at the critical temperature of $\pu{31.1^...
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3answers
122 views

What is the term used as correction for attractive forces in the Van der Waals Equation?

I have seen a question in my textbook which is little bit confusing, The term that corrects for attractive forces present in real gas in van der Waal equation is (i) ${nb}$ (ii) $\frac{an^2}...
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1answer
521 views

Why do different gases have the same molar volume?

Molar volume: The molar volume, symbol $V_\mathrm m$ is the volume occupied by one mole of a substance (chemical element or chemical compound) at a given temperature and pressure. At S.T.P ...
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2answers
76 views

Doesn't the isothermal irreversible expansion/compression of an ideal gas law violate the ideal gas law? [closed]

Let's say a cylinder has some ideal gas. We use a piston to suddenly expand the gas in isothermal condition from $1\ \mathrm{atm}$, $20\ \mathrm L$ to $0.5\ \mathrm{atm}$, $50\ \mathrm L$. Since the ...
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1answer
36 views

Heat generation in exothermic reactions [duplicate]

Im thinking specifically of N2 + 3 H2 ⇌ 2 NH3. Its an exothermic reaction, therefore heat is generated. Im trying to understand how Chateliers principle interacts with this reaction. I understand that ...
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1answer
309 views

What percentage of a 20 volume solution is actually hydrogen peroxide? [closed]

Not too sure how to go about answering this question. I know that volume Strength is the volumes of O2 released on the decomposition of one volume of H2O2 at STP. However, I'm not certain where to go ...
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1answer
41 views

Сould you tell me, Henry's law depends on curvature of gas/liquid interface or not?

Could you tell me Henry's law depends on curvature of gas/liquid interface or not? It would be better with references. Thank you!
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0answers
41 views

How was it possible to accurately measure the mass of gases in the 19th century?

I have seen periodic tables of Mendeleev (1834-1907) and Newland (1837-1898) in which masses of gases such as oxygen and nitrogen were shown. I don't think there were instruments to measure mass of ...
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48 views

Stoichiometry question regarding Kp and amount

$$\ce{2 NH3 (g) -> N2 (g) + 3 H2 (g)}$$ I know the reaction, temperature (600 Celsius), pressure (1 bar), $K_p$ (equilibrium constant regarding pressure)=16,76, and initial $mol_{reactant}$=1 mol. ...
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1answer
534 views

Final pressure of an ideal gas mixture, when two separate gases are put into one vessel

At constant of 200 cm³ of $\ce{N2}$ at 720 mmHg and 400 cm³ of $\ce{O2}$ at 750 mmHg are put together into one litre flask. The final pressure of the mixture is: My question is how to use ideal gas ...
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1answer
54 views

Is there a better model than the Kinetic Theory of Gases [closed]

I'm looking for a better relationship between the Kinetic energy of a gas and it's Temperature, and also how they vary with gravity (not altitude, just gravity!). So is there a model better than the ...
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0answers
30 views

Is this the equation of state?

\begin{align} pn^{-\lambda} &= \text{constant} \tag1\label{eq:one}\\ pV^\lambda &= \text{constant} \tag{2, adiabatic equation} \label{eq:two}\\ n\left(\frac{l}{2}\right)\delta T &=...
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1answer
218 views

Dissolving of non polar gases in water (liquid)

How does dissolving happen for non polar gases in water? Is it like being in the space between the water molecules or does there occur some kind of interaction occur between gas molecules and water ...
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0answers
33 views

Total pressure conservation during equilibrium reaction

I tried to solve the following exercise but my solution is different from the one of the book and I can't understand why. The exercise is the following: With total pressure $$p_\text{tot}=\pu{0.5 ...
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1answer
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Why can we still breathe in valleys? [duplicate]

Air is 1% argon. Argon is heavier than air. Why doesn't the argon concentrate in low-lying areas, choking out life there?
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1answer
29 views

Measure of partial pressure on blood

Here is the issue of blood gases partial pressure. On medical reports is common to see partial pressure of gas on blood, usually oxygen, but there is no gas in equilibrium with blood, so it is ...
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2answers
88 views

Volume of composition of air

My teacher stated: At standard conditions, 1 liter of air at 21% oxygen possesses $\pu{0.21 L}$ of oxygen. Since at STP, 1 mole of gas occupies $\pu{22.4 L}$, simply divide $0.21/22.4$, to arrive ...
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0answers
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Gas concentrations along the gradient from sea level to deep-sea

Studying scuba diving-related phenomenas I thought about how to estimate gases concentration down the sea. Of course, solubility of gases at, for example, $5$ atm of pressure, can be estimated with ...
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1answer
47 views

How to apply Henry's law down the sea?

Background: Henry's law states that: At a constant temperature, the amount of a given gas that dissolves in a given type and volume of liquid is directly proportional to the partial pressure of ...
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4answers
489 views

Raoult's law & Dalton's law of partial pressures

I am confused between Raoult's law and Dalton's law of partial pressure as they state completely different things about same thing... Raoult's law claims $p = P \cdot x$ where $p$ is the partial ...
6
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1answer
584 views

Why is dp/dv zero for a real gas in critical conditions?

I have read this fact in various websites but cannot understand the reason. What is an intuitive explanation of this?
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1answer
50 views

Calibration Ammonia Sensor and Gas Concentration

My name is Felipe and this is my first post here. I'm working on a project to calibrate an electrochemical ammonia sensor. But I have a lot of doubts because I am a layman in chemistry. I'll list them ...
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2answers
108 views

Identifying an unknown gas using the Ideal Gas Law [closed]

So my chemistry teacher gave me this packet having to do with The Ideal Gas Law. One of the homework questions says, "An unknown gas at $\pu{20.0 ^\circ C}$ and $\pu{1900 torr}$ has a density of $\pu{...
2
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2answers
79 views

Avogadro's gas Law doesn't make sense? (it does actually)

It says equal volumes of all gasses under same conditions of temp. and pressure contains the same number of atoms/molecules. Now suppose you have 1L of Chlorine in a box and 1L Hydrogen in another ...
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1answer
321 views

Why does 1 mol. of any gas at STP occupy only 22.4L Volume when it should occupy the volume of entire container in which it is kept? [duplicate]

Let us say we have a container of 100L capacity and a gas inside it is kept at STP. According to the law the gas should occupy only 22.4L of volume but shouldn't the gas occupy the entire volume of ...
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1answer
34 views

Temperature of an aerosol can

Hey guys I just had a quick question regarding the temperature of a dust off can or other aerosol cans containing compressed gas. It is if I have a dust off can and I were to spray some gas from it, ...
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1answer
119 views

Trying to understand the contradiction in the data of Proust/Dalton/Berzelius vs Gay-Lussac

I am trying to understand some of the historical context behind the discovery of atoms (pre-Avogadro). In particular, I am getting stuck in reading the following documents: http://physics.unl.edu/~...
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1answer
48 views

High vapor pressure cooking

On a Wikipedia article about latent heat, it can be found: The large value of the enthalpy of condensation of water vapor is the reason that steam is a far more effective heating medium than ...
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64 views

Effusion rate 1.4 times faster SO2(g)

How do I solve this- Which diatomic gas would effuse at a rate that is 1.4 times faster than the rate at which so2(g) effuses at any given temperature? This is high school chemistry. I did: (using ...
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2answers
1k views

Ideal gas Law best describes the properties of which of the following gases at 0 degrees Celsius and 1 atm? [closed]

a. $\ce{PH3}$ b. $\ce{HBr}$ c. $\ce{SO2}$ d. $\ce{N2}$ I believe that it is $\ce{N2}$, but I'm not too sure, since technically all of them would act the same at STP.
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2answers
621 views

Graph of compressibility factor vs pressure when real gas is assigned Z=1

Problem: According to the real gas equation, $Z = 1$ for an ideal gas and $Z$ is variable for a real gas. Suppose, in order to easy our calculations, we fixed $Z=1$ for a real gas and for ideal ...
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1answer
105 views

van der Waals equation for deviation of gases from ideal behavior

$(P + an^2/V^2)(V - nb) = nRT$ I understand that the term $nb$ is subtracted from the volume term as the available volume for the gas molecules to move around decreases in the case of a real gas ...
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2answers
96 views

Volume of gas in containers

If gases occupy all the volume in a container then how can we define 'volume percent' as all different gases will have same volume?