PASCO TD-8565 Adiabatic Gas Law Apparatus - Manual (Page 6)

Experiment 1: Ideal Gas Law
© 2009 Physics Enterprises 6
Use the calculator to define nR = P ∙ V/T and choose Properties to ensure that the Numeric
display shows at least three significant figures. Plot a graph of nR by selecting the
appropriate title on the vertical axis.
Use the Σ icon on the Graph menu to display the mean value of nR as well as the
standard deviation.
nR
mean
= ______________ J/K Std. Dev. = _____________ J/K
What percentage of the mean is the standard deviation?
%random error = 100% ∙ Std. Dev./mean = _________ %
This is an estimate of the random errors associated with the experiment.
B. Number of mol, n
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
o
= _________ (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).
Compute your measured value of R.
R
mean
= (nR
mean
)/n = ___________ J/ mol·K
Compare your measurement with the generally accepted value of R = 8.314 J/ mol∙K.
Is this percentage greater or less than the standard deviation percentage?
Should the errors in this experiment be considered primarily random or systematic?
air
air
M
V
n
0
ρ
=
= ×
−
= % 100
314 . 8
314 . 8
% mean
R
Err ____________%
= __________ mol