How much does air weight?

[98 tigershark]

How much more does a pound of air weight at 32 degrees than at 90 degrees?

98 tigershark:fluffy:

[joecar]

1lb of air always weighs 1lb regardless of its temperature...

:)

a given mass of air at lower temperature occupies less volume than at higher temperature...

Are you asking how does the density of air change with temperature...?

[98 tigershark]

Hey Joe, you are right of course. I was having a little fun.
With that said a pound of warm air wont fit into the same space as a pound of cold air.
98 tigershark


1lb of air always weighs 1lb regardless of its temperature...

:)

a given mass of air at lower temperature occupies less volume than at higher temperature...

Are you asking how does the density of air change with temperature...?

[joecar]

lol... it was a trick question...;)

assuming pressure stays constant, then from PV = nRT we see: V/T = constant...

so then: V1/T1 = V2/T2

and then: V2/V1 = T2/T1

Going from 32°F (273.15K) to 90°F (305.37K): V2/V1 = 305.37K/273.15K = 1.118

So if a given mass of air goes from 32°F to 90°F at constant pressure (i.e. the volume is allowed to change), the volume increases by a factor of 1.118 (i.e. increases by 11.8%).

[mr.prick]

lol... it was a trick question...;)

assuming pressure stays constant, then from PV = nRT we see: V/T = constant...

so then: V1/T1 = V2/T2

and then: V2/V1 = T2/T1

Going from 32°F (273.15K) to 90°F (305.37K): V2/V1 = 305.37K/273.15K = 1.118

So if a given mass of air goes from 32°F to 90°F at constant pressure (i.e. the volume is allowed to change), the volume increases by a factor of 1.118 (i.e. increases by 11.8%).

But can you guess my weight? :laugh:

[redhardsupra]

check this baby out:
http://www89.wolframalpha.com/input/?i=air+density+at+30kpa+and+300K

[joecar]

check this baby out:
http://www89.wolframalpha.com/input/?i=air+density+at+30kpa+and+300KYeah, he's going to take over the world with Alpha... :hihi:

[nevinsb]

So which weighs more, a pound of feathers or a pound of gold?

[redhardsupra]

i dunno, drop both of them on your foot and tell me how equal they feel ;)

[98 tigershark]

216Lbs:throw::throw::throw:

But can you guess my weight? :laugh:

[mr.prick]

216Lbs:throw::throw::throw:

Lower

[98 tigershark]

186Lbs on a warm day?
:hihi::hihi::fluffy:

Lower

[mr.prick]

A little lower. :hihi:

[98 tigershark]

How much does a pound of air weight was somewhat for fun but! On older IE 1997-2004 I believe the IAT sensor is closer to the motor than the MAF and the MAF measures the weight of the air as it is taken in (G/S or Lbs and Hour). At start up after you have run your car for a while the motor compartment can give a much higher IAT temp reading at startup(less dense air by quite a bit). This was solved in later models were as the MAF and the IAT are one. I think the IAT needs to be exactly or as close to were the MAF is since it is measuring weight of the air. As Joe pointed out there is a difference in the volume at different temps. Of course a pound of air weights a pound but the temp will determine how much air by weight will fit into the cylinder. So it would seem the closer to the MAF the IAT sensor is the more accurate the PCM can compute the correct mass entering the cylinder along with the other sensors. The cylinder size is finite but the amount of the weight of air in the cylinder is a variable.
98 tigershark


lol... it was a trick question...;)

assuming pressure stays constant, then from PV = nRT we see: V/T = constant...

so then: V1/T1 = V2/T2

and then: V2/V1 = T2/T1

Going from 32°F (273.15K) to 90°F (305.37K): V2/V1 = 305.37K/273.15K = 1.118

So if a given mass of air goes from 32°F to 90°F at constant pressure (i.e. the volume is allowed to change), the volume increases by a factor of 1.118 (i.e. increases by 11.8%).