A 4.40 mol sample of an ideal diatomic gas expands adiabatically from a volume of 0.121 m3 to 0.60 m3. initially the pressure was 1.00 atm. (assume no molecular vibration.) (a) determine the initial and final temperatures.

Respuesta :

First, we have to get Pf from this formula:

Pf = Pi * (Vi/Vf)^γ

when Pi = 1 atm = 1* 1.01325 x 10^5 Pa

Vi = 0.121 m^3

Vf = 0.6 m^3

and gamma γ = 1.4 

by substitution:

Pf = 1 atm * (0.121 /0.6 )^1.4

       = 0.11 atm = 11145.75 Pa

a) to get initial T:

when Pivi = nRTi 

by substitution

(1.01325 x 10^5)*0.121  = 4.4 * 8.31 * Ti 

∴Ti = 335 K


b) to get Tf :

PfVf = nRTf

by substitution:

11145.75 * 0.6 = 4.4 * 8.31 * Tf

∴ Tf = 183 K