PASCO TD-8565 Adiabatic Gas Law Apparatus - Manual (Page 10)

Experiment 2B: Work Done by an Isothermal Process
© 2009 Physics Enterprises 10
B. Calculate the number of mol of gas from the density of air at STP of ρ= 0.00129 g/cm 3 , the
initial volume V
0
(in cm 3 ) and the molecular weight of air M
air
= (0.8*28+0.2*32) g/mol
(assuming 80% nitrogen and 20% oxygen).
C. Record the initial and final heights for the piston,
h
i
= _________ cm h
f
= ___________ cm
Calculate the theoretical value of the work from the ratio of the initial to final height.
air
air
M
V
n
0
ρ
=
=
⎟
⎟
⎠
⎞
⎜
⎜
⎝
⎛
=
⎟
⎟
⎠
⎞
⎜
⎜
⎝
⎛
=
f
i
f
i
theory
h
h
nRT
V
V
nRT W
ln ln
= ×
−
= % 100 %
theory
theory
W
W area
Err
= __________ mol
____________%
____________ J