Chlorine Gas
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6e4d919460db43abae1af1474c7b7315
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Chlorine Gas
We are studying gas laws. In Avagadro’s Law, it says that 22.4L = 1 mol at STP. When we looked at a graph included in our book, is showed that obviously ideal gas is 22.41L but Chlorine gas is only 22.06L. Is there a reason that Chlorine gas volume is so low? I tried to add a picture but it wouldn’t upload. The book is “The Central Science” figure 10.10
Re: Chlorine Gas
Hi there,
Gas laws only apply to ideal gasses--basically this simplifies the actual physical properties of gasses. These simplifications are that gas molecules take up a negligible amount of volume, and do not repel or attract each other.
In reality, this isn't true for most gasses. What you are seeing with chlorine is that it is a non-ideal gas, so it won't follow those rules exactly.
If you want to learn more, check out https://chem.libretexts.org/Textbook_Ma ... Real_Gases
Hope that helps.
Erin
Gas laws only apply to ideal gasses--basically this simplifies the actual physical properties of gasses. These simplifications are that gas molecules take up a negligible amount of volume, and do not repel or attract each other.
In reality, this isn't true for most gasses. What you are seeing with chlorine is that it is a non-ideal gas, so it won't follow those rules exactly.
If you want to learn more, check out https://chem.libretexts.org/Textbook_Ma ... Real_Gases
Hope that helps.
Erin
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6e4d919460db43abae1af1474c7b7315
- Posts: 2
- Joined: Thu Dec 06, 2018 3:17 pm
- Occupation: Student
Re: Chlorine Gas
Thank you for your response!
It was odd to me that in this chart, the other gases shown (carbon dioxide, ammonia, nitrogen, helium, and hydrogen) were all close to the ideal gas volume or 22.41 except chlorine. All of the elements except chlorine all were between 0.01 L above 22.41 and 0.1 L below. Helium is even exactly 22.41. It was strange to me that chlorine was 0.35 L below the ideal gas.
When I raised my hand and asked the question, my teacher was puzzled as well and never realized the difference. He asked me to try to find an answer and I have searched and came up empty handed. I know that the ideal gas doesn’t actually exist, I’m just wondering if there is a specific reason that chlorine is so much lower than other elements.
If you have an answer, that would be great! If not, thats okay too
It was odd to me that in this chart, the other gases shown (carbon dioxide, ammonia, nitrogen, helium, and hydrogen) were all close to the ideal gas volume or 22.41 except chlorine. All of the elements except chlorine all were between 0.01 L above 22.41 and 0.1 L below. Helium is even exactly 22.41. It was strange to me that chlorine was 0.35 L below the ideal gas.
When I raised my hand and asked the question, my teacher was puzzled as well and never realized the difference. He asked me to try to find an answer and I have searched and came up empty handed. I know that the ideal gas doesn’t actually exist, I’m just wondering if there is a specific reason that chlorine is so much lower than other elements.
If you have an answer, that would be great! If not, thats okay too
Re: Chlorine Gas
Hello! You have a great observation and a great question about why chlorine has greater deviation from ideal gas behavior compared to the other gases in your book!
As Erin mentioned, there are simplifying assumptions made for the ideal gas law. A couple of the major assumptions made are that 1) gas molecules do not take up space, and 2) gas molecules do not interact. In reality, all gases take up some space and interact to some extent via dipole-dipole interactions, London dispersion forces, etc. (some more than others).
There are many equations that are more complicated than the ideal gas law that try to take into account those two factors and more. One such equation is the Van Der Waals equation. It gives more "correct" answers compared to the ideal gas law, but it is not as convenient as the ideal gas law because you have to know specific "constant values" for whatever gas you are talking about. Check it out: https://en.wikipedia.org/wiki/Van_der_Waals_equation
If you look up the "constant values" for different gases, you can see that Chlorine has larger constants compared to some of the other gases you mentioned. For one, it is bigger. And for two, there are greater intermolecular forces. So that helps explain why it deviates from the ideal gas law more than other gases. Here's a table of the constants for various gases: https://en.wikipedia.org/wiki/Van_der_W ... data_page)
I hope this helps!
-Megan
As Erin mentioned, there are simplifying assumptions made for the ideal gas law. A couple of the major assumptions made are that 1) gas molecules do not take up space, and 2) gas molecules do not interact. In reality, all gases take up some space and interact to some extent via dipole-dipole interactions, London dispersion forces, etc. (some more than others).
There are many equations that are more complicated than the ideal gas law that try to take into account those two factors and more. One such equation is the Van Der Waals equation. It gives more "correct" answers compared to the ideal gas law, but it is not as convenient as the ideal gas law because you have to know specific "constant values" for whatever gas you are talking about. Check it out: https://en.wikipedia.org/wiki/Van_der_Waals_equation
If you look up the "constant values" for different gases, you can see that Chlorine has larger constants compared to some of the other gases you mentioned. For one, it is bigger. And for two, there are greater intermolecular forces. So that helps explain why it deviates from the ideal gas law more than other gases. Here's a table of the constants for various gases: https://en.wikipedia.org/wiki/Van_der_W ... data_page)
I hope this helps!
-Megan