Chemistry Stack Exchange
Chemistry Stack Exchange

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.

Physical and chemical laws describing the properties and behavior of gases; relationships between the pressure, volume, and temperatures of gases. Specific examples include, but are not limited to:

  • Ideal gas law: that gives us the ideal gas equation: pV = nRT
  • Henry's law: relates the mole fraction of a gas dissolved in solution to its partial pressure
  • Dalton's law: relates the partial pressure of gases to their mole fraction in the container
  • Raoult's law: relates the vapour pressure of immiscible solvents with their mole fractions
  • Charles' law: relates volume to temperature at constant pressure
  • Gay-Lussac's law: refers to two different laws: 1) The ratio between the volumes of the reactant gases and the gaseous products can be expressed in simple whole numbers. 2) The pressure of a gas of fixed mass and fixed volume is directly proportional to the gas's absolute temperature.
  • Avogadro's law: equal volumes of all gases, at the same temperature and pressure, have the same number of molecules
  • Amagat's law: According to Amagat’s law of partial volume, the total volume of a non-reacting mixture of gases at constant temperature and pressure should be equal to the sum of the individual partial volumes of the constituent gases
  • Graham's law: relates the rate of diffusion of a gas to its molar mass
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Why would breathing pure oxygen be a bad idea?

My textbook mentions that SCUBA tanks often contain a mixture of oxygen and nitrogen along with a little helium which serves as a diluent. Now as I remember it, divers take care not to surface too quickly because it results in 'the Bends', which…
paracetamol
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What volume does one mole of an ideal gas occupy?

This has been bugging me for a while now... Obviously, to calculate the volume/space occupied by a mole of (an ideal) gas, you'll have to specify temperature ($T$) and pressure ($P$), find the gas constant ($R$) value with the right units and plug…
paracetamol
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Why can we still breathe in valleys?

Air is 1% argon. Argon is heavier than air. Why doesn't the argon concentrate in low-lying areas, choking out life there?
Stack Tracer
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Why are equations of state for a non-ideal gas so elusive?

The ideal gas equation (daresay "law") is a fascinating combination of the work of dozens of scientists over a long period of time. I encountered Van der Waals interpretation for non-ideal gases early on, and it was always somewhat in a…
jonsca
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What is a rigorous definition of gas volume, and how is the Van der Waals equation derived?

I am confused about the justification for the corrections to the ideal gas law in the Van der Waals equation: $$p=\frac{nRT}{V-nb}-a\left(\frac{n}{V}\right)^2$$ I understand that the equation attempts to correct for attractive and repulsive forces…
Sean Mackesey
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Why is the van der Waals coefficient b equal to four times the volume of the particle?

In the van der Waals equation of state $$\left[p + a\left(\frac{n}{V}\right)^2\right](V-nb) = nRT$$ the coefficient $b$ is supposed to represent the volume occupied by the particles. Why then is it equal to four times the volume and not simply the…
piyush pachauri
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How could the ideal gas law be discovered from experiments on real gases?

The gas laws, namely Boyle's Law, Charles' Law, Avogadro's Law and Gay-Lussac's Law, are all experimental laws. Combining these laws, we get the ideal gas law $pV=nRT$. Also, "real life" gases do not exactly follow this law, so there are more laws…
user44637
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What's the difference between perfect and ideal gas?

There are all kinds of different dinstinctions in the internet, and I'd like to see what you guys thought. Actually, I've been asked if the heat capacity of an ideal gas es independent of temperature. I've said no, even though it's practically…
DLV
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Why don't heavy and light gases separate in the atmosphere?

Everyone must have heard that balloons are filled with helium, and the fact associated with it that helium gas is light and light gases always go upward. There comes a question to mind: if the molar mass of $\ce{CO2}$ is greater than that of…
Vidyanshu Mishra
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Why is the carbon dioxide we exhale transparent?

Why is carbon dioxide that comes from dry ice opaque and smoky while the carbon dioxide that we exhale transparent?
Krikor Ailanjian
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PV=nRT approximation on other planets?

In Chemistry class yesterday, I learned that real gases with low atomic masses behave like an ideal gas at high temperatures and low pressure. Since on earth at sea level the pressure is close to $1\ \mathrm{atm}$ (which is a low pressure) and…
James Smith
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When I heat up a balloon, does the air inside increase in pressure as well as volume?

When I heat up a balloon, does the air inside the balloon increase in pressure as well as volume? I thought pressure and volume were inversely proportional? Or does pressure and volume increase as temperature increases?
John
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How does composition of air affect vapor saturation limit?

Suppose we hold temperature, pressure, and gas composition (say, a standard atmosphere) constant. Then we know that if we allow the water content of the air to vary it can range between 0 and some saturation limit S g/L. How does that saturation…
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Why do helium balloons expand in volume as they go higher?

I realize as balloons go higher, the atmospheric pressure decreases, doing less to counteract the force of the gas particles pushing against the inner walls of the balloon. But at the same time, doesn't the outside temperature decrease, causing the…
Nick
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Why do some gases have lower value of Z for a particular pressure?

In the above graph,the minima of the curve for methane is more than that of nitrogen. Also, for a given value of pressure, the value of $Z$ for methane is less than that of nitrogen. They seem to meet at high pressure. Why do some gases have lower…
Aditya Dev
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