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Order
0
th
1
st
2
nd
rate law
r = k
r = k[A]
r = k[A]
2
units for k
ex.:
integrated rate
expression
or
or
plot as y
[
A
]
ln [
A
]
plot as x
t
t
t
slope
!
k
(neg. slope)
!
k
(neg. slope)
k
(pos. slope)
yintercept
[
A
]
0
ln[
A
]
0
t
1/2
[]
A
k
0
2
conc
time
M
sec
Ms
⋅
−
1
1
time
1
min
min
−
1
1
conc time
⋅
1
e
c
⋅
−−
⋅
11
Ak
t
A
t
=−
+
0
ln[ ]
ln[ ]
t
A
t
+
0
ln
A
A
kt
t
0
[] []
AA
e
t
kt
=
−
0
0
A
kt
A
t
=+
1
A
1
0
A
0 693
.
k
1
0
kA
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View Full DocumentChemistry 122/125 — Experiment 17 Lab Report Tips
1.
When graphing
you can use a computer to do the graphs.
If your graphing program does regression analysis or “trend
lines” (least squares fitting) you can use this to plot your lines as well.
Some programs can also draw nice smooth
nonlinear curves.
If you use the trend line produced by the computer you need to include, both on the graph and in your
report, the equation the computer gives you for the line.
You should also report the correlation coefficient (usually
signified as R or R
2
) which gives you some idea how good the fit is.
The closer R is to ±1 (R
2
= 1) the better your fit is to
a trend line, i.e. the closer your points are to falling on trendline (R=±l means all your points should fall exactly on the
chosen trend line).
Some programs report a X
2
or variance of the fit, s
t
2
which tell you how good the fit is.
Report these if
given.
If your program can not do a regression analysis (trend line) than just have it plot the points and you draw the “bestfit”
curve.
This means you have to compute the slope yourself (if using a linear fit).
To do this accurately and correctly you
need to have the plotting program draw grid lines so it looks something like the graph paper provided in your lab manual.
Having a few tick marks at 0.5 inch intervals will not be acceptable.
For all graphs, whether by hand or computer generated, they should occupy essentially the whole page.
In other words,
spread out your axes so your data occupies as much of the graph and page as possible.
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 Winter '08
 Zellmer

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