Discover the Gas with the Lowest Adiabatic Index at Room Temperature

In summary, the gas with the lowest adiabatic index at room temperature is octafluoropropane, also known as Freon 218, with a ratio of specific heats of approximately 1.066. It is a very common, non-flammable and non-toxic gas. Other options with low adiabatic index include butane, octane, propane, and ethane, but their toxicity levels are uncertain.
  • #1
Sunfire
221
4
Hello,

to the best of your knowledge, what is

1) the gas with the lowest adiabatic index ##\gamma=\frac{c_p}{c_v}## at room temperature
2) a very common, non-flammable, non-toxic gas with the lowest adiabatic index at room temperature

Many thanks
 
Engineering news on Phys.org
  • #2
In general, you're looking for molecules with the largest number of atoms. Octafluoropropane, also called Freon 218, has a ratio of specific heats of ~1.066 at room temperature and atmospheric pressure. Regarding toxicity, check the http://msdssearchengine.com/local_msds.php?id=118976.
 
  • Like
Likes 1 person
  • #3
Just dug out the old thermo book...300 K and 1 ATM

Butane 1.091
Octane 1.044
Propane 1.126
Ethane 1.186

Those are the lowest ratios I found, not sure on toxicity though. However, I'm going to guess they're a heck of a lot less toxic than anything with Chlorine or Flourine in it...
 

1. What is the lowest adiabatic index and why is it important in science?

The lowest adiabatic index, also known as the adiabatic exponent or ratio of specific heats, is a quantity that describes the relationship between pressure and volume in a gas or fluid. It is important in science because it helps us understand how gases and fluids behave under different conditions, such as changes in temperature or pressure. It is also a key factor in many thermodynamic calculations and equations.

2. How is the lowest adiabatic index calculated?

The lowest adiabatic index is calculated by taking the ratio of the specific heats at constant pressure (Cp) and constant volume (Cv) for a given substance. In other words, it is equal to Cp/Cv. This value can vary depending on the type of substance and its physical state.

3. What is the significance of the lowest adiabatic index in atmospheric science?

In atmospheric science, the lowest adiabatic index plays a crucial role in understanding the behavior of air parcels as they rise or sink in the atmosphere. This parameter is used to calculate changes in temperature and pressure as air rises or sinks, and is a key factor in determining atmospheric stability and the formation of clouds and precipitation.

4. How does the lowest adiabatic index differ from the highest adiabatic index?

The lowest adiabatic index is typically associated with gases or fluids that have a low molecular weight and are easily compressible, such as air or helium. On the other hand, the highest adiabatic index is associated with substances that have a high molecular weight and are difficult to compress, such as solids or liquids. The values of these two indices can vary significantly and have different implications in different fields of science.

5. Can the lowest adiabatic index change under different conditions?

Yes, the lowest adiabatic index can change under different conditions, such as changes in temperature, pressure, or composition of a gas or fluid. For example, the lowest adiabatic index for a gas may be different at sea level compared to at high altitudes due to differences in air density and pressure. Additionally, the lowest adiabatic index can also vary for different substances, as each substance has its own unique properties and behaviors.

Similar threads

Time to empty gas cylinder (problem worked, but would like feedback)
    • Mechanical Engineering
Replies
7
Views
737
I Graphical difference between adiabatic and isothermal processes.
    • Thermodynamics
Replies
1
Views
637
Closed cycle of an ideal gas
    • Introductory Physics Homework Help
Replies
3
Views
118
I Irreversible adiabatic processes & entropy change (clarification needed)
    • Thermodynamics
Replies
22
Views
2K
Combustion of an explosive liquid bubble
    • Introductory Physics Homework Help
Replies
2
Views
2K
I Solving Adiabatic Process for Two Compartments
    • Classical Physics
Replies
1
Views
916
Total force from air spring model (double acting piston)
    • Mechanical Engineering
Replies
8
Views
1K
Adiabatic Expansion of Pressurized Air in a Piston-Cylinder Setup
    • Introductory Physics Homework Help
Replies
8
Views
742
Adiabatic Reversible Compression of a Solid
    • Advanced Physics Homework Help
Replies
16
Views
3K
A Adiabatic Compressible Flow in a Converging Duct
    • Classical Physics
Replies
6
Views
1K

Hot Threads

Recent Insights

Back
Top