# How can I mix gases in a chamber measuring only pressure and temperature

• electr0dave
In summary: Please give it a shot. Let V be the volume of the chamber and T be the temperature, and do everything algebraically. Let's see what you come up with. If you have trouble, I'll help.In summary, the goal is to keep the pressure inside the chamber constant by controlling the CO2 concentration.
electr0dave
Hello all!

Basically I intend to create an environment inside a chamber with variations of CO2 percentages, using electrovalves.
The mixing gas is always compressed air + CO2.

For example: create a 50% CO2 concentration with a total pressure of 2 Bar.
The chamber is closed, and compressed air is introduced up to 1 bar. Then CO2 is introduced until Ptotal reaches 2 bar.

The problem is that with this gas mixture, the chamber will be heated until 50°C, varying the pressures inside.

Can someone help me with some calculations? I am an electronics engineer and so chemistry and thermodynamics aren't my strong ones.

PS: The chamber will have an unknown volume, given that inside it will be placed parts also of variable volume.

What is the initial state of the pure gases and what is the final state of the mixture?

electr0dave

Initially the chamber has air at ambient pressure.
I fill the chamber with compressed air (coming from a compressor) to 2 bar and then close the solenoid valve and open an electrovalve that only escapes that air (until pressure "0"). A kind of renewal cycle.
Then I open the valve of the compressed air again until P1, close it, and open the valve of the CO2 cylinder until the pressure P2.

Inside the chamber will be an object that absorbs CO2. The aim is to control and monitor the pressure inside the chamber.

By measuring the total pressure variation I must get a good approximation (knowing that the object only absorbs CO2) from how much CO2 was absorbed.

electr0dave said:

Initially the chamber has air at ambient pressure.
I fill the chamber with compressed air (coming from a compressor) to 2 bar and then close the solenoid valve and open an electrovalve that only escapes that air (until pressure "0"). A kind of renewal cycle.
Then I open the valve of the compressed air again until P1, close it, and open the valve of the CO2 cylinder until the pressure P2.

Inside the chamber will be an object that absorbs CO2. The aim is to control and monitor the pressure inside the chamber.

By measuring the total pressure variation I must get a good approximation (knowing that the object only absorbs CO2) from how much CO2 was absorbed.
If you don't know the volume available for gas in the system, you won't be able to get the absolute amount of CO2 absorbed...only the fraction of the CO2 absorbed. Also, P2 must of course be higher than P1.

Are you familiar with the ideal gas law?

Chestermiller said:
If you don't know the volume available for gas in the system, you won't be able to get the absolute amount of CO2 absorbed...only the fraction of the CO2 absorbed. Also, P2 must of course be higher than P1.

Are you familiar with the ideal gas law?

Hello.
I need to distinguish which object absorbs more CO2. So a comparison of fraction is sufficient.

As for the pressure P2, I wanted to refer to the pressure above P1.
Therefore, in the example, P1 = 1bar and P2 = Ptotal = 2bar (or 1 bar above P1).

I am familiar with the ideal gas law.
Can I take the volume out of the equation? It will be the same in both gases ... just like the temperature.
But the temperature will affect the gases in different ways, right? It will depend only on the ratio of the number of moles ...

I can understand this in my head, but I can not find a mathematical basis for the problem ...

electr0dave said:
Hello.
I need to distinguish which object absorbs more CO2. So a comparison of fraction is sufficient.

As for the pressure P2, I wanted to refer to the pressure above P1.
Therefore, in the example, P1 = 1bar and P2 = Ptotal = 2bar (or 1 bar above P1).

I am familiar with the ideal gas law.
Can I take the volume out of the equation? It will be the same in both gases ... just like the temperature.
But the temperature will affect the gases in different ways, right? It will depend only on the ratio of the number of moles ...

I can understand this in my head, but I can not find a mathematical basis for the problem ...
Please give it a shot. Let V be the volume of the chamber and T be the temperature, and do everything algebraically. Let's see what you come up with. If you have trouble, I'll help.

## 1. How do I calculate the ideal gas law to mix gases in a chamber?

The ideal gas law, PV = nRT, can be used to calculate the number of moles of each gas present in the chamber. This information can then be used to determine the ratio of gases needed to achieve the desired mixture.

## 2. What is the relationship between pressure and volume when mixing gases in a chamber?

The relationship between pressure and volume is described by Boyle's Law, which states that at a constant temperature, the pressure of a gas is inversely proportional to its volume. This means that as the pressure increases, the volume decreases, and vice versa.

## 3. Can I mix gases with different molecular weights in a chamber?

Yes, it is possible to mix gases with different molecular weights in a chamber. The ideal gas law and Dalton's law of partial pressures can be used to calculate the partial pressure of each gas and determine the overall pressure of the mixture.

## 4. How can I ensure a homogeneous mixture of gases in the chamber?

To ensure a homogeneous mixture of gases, it is important to thoroughly mix the gases before taking measurements. This can be achieved by using a mechanical mixer or by allowing the gases to diffuse and equilibrate over time.

## 5. What factors can affect the mixing of gases in a chamber?

The mixing of gases in a chamber can be affected by factors such as temperature, pressure, gas flow rates, and the presence of other substances in the chamber. It is important to carefully control these variables to achieve an accurate and consistent gas mixture.

• Thermodynamics
Replies
3
Views
966
• Thermodynamics
Replies
3
Views
951
• Thermodynamics
Replies
4
Views
1K
• Introductory Physics Homework Help
Replies
4
Views
575
• Thermodynamics
Replies
11
Views
7K
• Introductory Physics Homework Help
Replies
16
Views
1K
• Materials and Chemical Engineering
Replies
2
Views
257
• Thermodynamics
Replies
22
Views
2K
• Thermodynamics
Replies
4
Views
1K
• Thermodynamics
Replies
1
Views
4K