Can Air Be Treated as an Ideal Gas in Absolute Zero Calculations?

Click For Summary

Homework Help Overview

The discussion revolves around the experimental determination of absolute zero and the applicability of the ideal gas law to air in this context. The original poster expresses concern about their calculated value of absolute zero, which significantly deviates from the theoretical value of -273°C, and questions whether air can be treated as an ideal gas for these calculations.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to understand the implications of treating air as an ideal gas in their calculations and seeks clarification on the accuracy of their experimental results compared to the accepted value of absolute zero.

Discussion Status

Some participants provide insights into the reliability of the ideal gas approximation for air at various temperatures, suggesting that it remains valid up to at least -100 degrees Celsius. However, there is no explicit consensus on the original poster's calculations or the reasons for the discrepancy in their results.

Contextual Notes

The original poster's calculations are part of a lab assignment, and they are not seeking direct solutions but rather guidance on their approach and assumptions regarding the ideal gas behavior of air.

hover
Messages
342
Reaction score
0

Homework Statement


Calculate your experimental value of absolute zero , how does your experimental value compare to the theoretical value -273C?


Homework Equations


T_abs=(S1*T2-S2*T1)/(S1-S2)


The Attempt at a Solution



This is all part of a lab. I'm not asking people to do any calculations. I'm more worried about my calculations from what I got and I'm pretty sure I did them correctly. The accepted value for absolute zero is -273C. The value I got when calculating was -72.18 C. My question is can air be treated as an ideal gas so that the calculation on absolute zero is possible? If air can't be treated as an ideal gas then it would explain the huge difference in my value vs the accepted value.

Thanks!
 
Physics news on Phys.org
The ideal gas approximation is VERY good for air near room temperature. I'd say it's extremely accurate up to at least -100 degrees Celsius.
 
ideasrule said:
The ideal gas approximation is VERY good for air near room temperature. I'd say it's extremely accurate up to at least -100 degrees Celsius.

So that means I did something wrong right?
 
Yes, I'd say so. You should be able to get a reasonable value (within 50 degrees or so of the actual answer).
 
ideasrule said:
Yes, I'd say so. You should be able to get a reasonable value (within 50 degrees or so of the actual answer).

ok. thanks for letting me know
 

Similar threads

Open Gas Turbine - calculate T2, T3, T4, efficiency
  • · Replies 1 ·
Replies
1
Views
2K
Adiabatic Expansion of Pressurized Air in a Piston-Cylinder Setup
  • · Replies 8 ·
Replies
8
Views
2K
Mixing two ideal gases with different V, T at constant pressure
  • · Replies 16 ·
Replies
16
Views
4K
Thermodynamics of a Single-Component Ideal Gas
  • · Replies 1 ·
Replies
1
Views
2K
Trouble solving for end state of two control volumes in a rigid tank
  • · Replies 12 ·
Replies
12
Views
2K
PV Diagram of Ideal Monatomic Gas Processes
  • · Replies 4 ·
Replies
4
Views
2K
Ideal gas in a cylinder with a piston
  • · Replies 5 ·
Replies
5
Views
11K
Ideal Gas Law Homework: Calculating Number Density and Spacing Between Molecules
  • · Replies 2 ·
Replies
2
Views
2K
Calculating Internal Energy & Temperature Change of Ideal Gas
  • · Replies 1 ·
Replies
1
Views
2K
Ideal Gas Equation and Polytropic Constant
  • · Replies 3 ·
Replies
3
Views
7K