PASCO TD-8565 Adiabatic Gas Law Apparatus - Manual (Page 8)

Experiment 2A: Boyle’s Law
© 2009 Physics Enterprises 8
Analysis
A. Use the Calculator to compute the ln(P) and ln(V) and make a graph of ln(P) on the y-axis
vs. ln(V) on the x-axis. Perform a linear fit and record the slope:
Slope = __________
Compare this with -1.0 as expected for an inverse proportion.
B. Since P = nRT/V, use the Calculator to obtain 1/V and plot P vs. 1/V. Perform a linear fit and
record the slope:
nRT = Slope = _____________
Calculate the volume of air (in cm 3 ) at the initial 10 cm height when the stopcock was
open to the atmosphere using
V
0
= π r 2 h = _________ (cm 3 )
where r is half the diameter displayed on the label of the Adiabatic Gas Law Apparatus.
Calculate the number of mol of gas from Eq. (1.3), with the density of air at STP of ρ =
0.00129 g/cm 3 , the volume V
0
, and the molecular weight of air M
air
= (0.8*28+0.2*32) g/
mol (assuming 80% nitrogen and 20% oxygen).
From a plot of T vs. time, use the Σ statistics tool to find the mean (room temperature),
T = __________ K
Now calculate R, R = (nRT)/n·T = (slope)/n·T = __________
Compare your measurement with the generally accepted value of R = 8.314 J/mol∙K.
air
air
M
V
n
0
ρ
=
= ×
−
= % 100
314 . 8
314 . 8
% mean
R
Err
= __________ mol
____________%