[IDudeScience]

Do I just take my Keq value and Ln it? Or is there a different way? Thanks need answer asap

[Grundalizer]

Need some more info, wtf are you trying to do?  Pretend you are a stranger, and you read your request...could you figure out what you are trying to do?

[IDudeScience]

I'm trying to find the ln of Keq. I am supposed to plot a 1/T vs lnKeq graph

Equation is Fe3+ + SCN- --> FeSCN 2+

[Grundalizer]

I remember this lab.  I am guessing you made the Iron cyanate complex, and it was orange colored?  You use a Spec 20 or UV/Vis spectrophotometer to find lambda max?  

If you plot your absorption vs concentration, you should be able to come up with a graph in excel, then using the, "add trendline" "show equation" you should be able to get what you are looking for.  

Sorry, I probably have that lab handout somewhere in my messy room...but I couldn't find it easily.  I don't remember the equations associated with the absorption shiz.

So, like you said, go into excel.

put in a cell, =(1/(Insert cell letter and number here)   (where the cell is the data points for T, or transmittance)

and in the other column, put =ln(insert cell and number here) 

then drag it down the length of the column, and it will auto input that formula for all the data points.  Excel is a b$*%(, but its cool once you get to know it.

[IDudeScience]

yeah i thikn my graph is wrong... only two points go thru the best fit line its all over the place... my lnk values are:

5.44 5.45 .5.48 5.56 5.58 5.64 5.66 5.74

Vs

1/t

0.00296 0.00310 0.00317 0.00324 etc

[IDudeScience]

Am I suppose to get a line facing like this \? Mine's like this /

[Grundalizer]

Make sure you do an X,Y scatter plot.  I think yours is the right way.  F...I always used to do my graphs backwards. 

My prof told me, easy way to remember.  Whatever you are MEASURING with an instrument, should be on the y axis.  I think...

[Grundalizer]

Sorry I'm not of more help. 

Try googling it, its a very common lab.

I found this, http://www.usm.maine.edu/chy/manuals/116/text/KeqSpec.html  and I am sure there are many others