# Pressure of a gas in atmospheres at different temperatures

## Main Question or Discussion Point

A chemist measured the pressure of a gas in atmospheres at different temperatures in
°C:
Temp (°C) -136 -25 0 25 100 273
Pressure (atm) 0.50 0.91 1.00 1.09 1.37 2.00
Can you predict the temperature at which the pressure would equal zero?

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BruceW
Homework Helper
Its a complicated question, because the relationship between temperature and pressure in the atmosphere is not linear at all. The atmosphere has several different 'sections' as you go higher up, so the behaviour changes.

this prob was actually posted to me by a webhosting company, i applied there for a job. so i really need to nail this.

never took physics, guess the physics gods are taking revenge now :-(

Doc Al
Mentor
I don't think the question has anything to do with the atmosphere (which would certainly complicate things) but just that it measures the gas pressure in atmospheres.

My suggestion: Change to an absolute scale of temperature (°K instead of °C) and draw a plot of pressure vs temperature.

You lost me. I understand plotting, but Id still have to come up with the the temperature at which the pressure would equal zero..

Doc Al
Mentor
Did you do what I suggested?

BruceW
Homework Helper
OH! Ah, I see you were only mentioning 'atmospheres' as a measure of the pressure. Sorry, I totally misunderstood you.

Honestly, I dont know how. Never took physics.

BruceW
Homework Helper
Doc Al has the right idea. You should plot temperature on one axis and pressure on the other, then see what you get. From this you might be able to infer the temperature at which pressure is zero.

Doc Al
Mentor
If you do nothing else, just make a plot of pressure versus temperature and see what it looks like.

(You don't even really need to change the temperature scale, since they are proportional.)