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Question about Atmospheric pressure

  • #1

Homework Statement


The problem is this: If T(temperature) AND P(pressure) of air increases, what can we assume about D(density)?


Homework Equations


Well, I know that as temperature increases, pressure increases and vice versa. When you try this question out with the equation P=KdT it doesn't quite make sense. It all depends on how much the pressure increases and how much the temperature increases, correct? Let's say the pressure goes up from 33 KPa to 101.32 KPa but the temperature only goes from 233 Kelvin to 235 kelvin. Both the P and T increased but the density would increase. However, if the pressure only goes up by, say, 5 mb and the temperature increases from 20 K to 308 K then the density would decrease. If the pressure and temperature increase by the same rate (corresponding to the equation) then the density would remain the same.


The Attempt at a Solution


At first i said decrease, but then I assumed that my teacher meant that if P and T increase an equal amount, so I said density would stay the same. What is your guys' opinion on how to answer this? Would you say it depends on how much the T and P goes up or would you say it would remain the same? Or is there a different, correct solution? Thanks everyone. Any input is appreciated

Homework Statement





Homework Equations





The Attempt at a Solution

 
Last edited:

Answers and Replies

  • #2
993
13
Why don't we assume ideal gas conditions and start from

PV=nRT where n is the number of moles

and try to modify above equation to the form P=KdT?
 
  • #3
Borek
Mentor
28,360
2,753
It all depends on how much the pressure increases and how much the temperature increases, correct?
Yes.
 

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