# Heating Time of Compressed Air

1. Oct 8, 2007

### s.p.q.r

HI,

If you compressed 300 litres (about 12 moles) into a 3 litre cylinder which was already at 3,000 degrees C. Would the air reach this temperature in an instant?

Im trying to get my head around this stuff about heat capacities and amounts of energy needed to heat materials.

PS- This isnt homework (im not even a physics student).

2. Oct 8, 2007

### s.p.q.r

I should mention that the tank that it will heat in is more of a long pipe.

3. Oct 8, 2007

### Staff: Mentor

Here is a nice explanation about adiabatic processes as well as a calculator to do the calculation you want.

The only way for air to reach a given temperature "in an instant" is for the process to be adiabatic. This means that there is no heat transfer. If there must be any heat transfer then the process cannot be "in an instant" since heat transfer always takes time.

On that calculator, plugging in 12 moles, .3 m^3 initial volume, .003 m^3 final volume, and an initial temperature of 273 K, you get a final temperature of 5800 K (which is about the temperature of the sun, so I may have punched in the numbers wrong, you had best do the calculations yourself).

Last edited: Oct 8, 2007
4. Oct 10, 2007

### s.p.q.r

Hi,

Great thanks for this link. It is helpful to understand why they must cool down compressors.

Cheers.

5. Oct 11, 2007

### keinve

it would hate quickly, no doubt about it, but it would take some time. that, and the cylindar would expload.