Suffering from a deviated standard.

The semester is in full swing and I feel like I am off to a fairly strong start.  As long as I can keep it up, I have no doubt I'll be able to pull of the GPA I need to get back on track.

Calculus and Organic Chem. are the same.  Organic Chem lab is insane and my professor is Crazy-Scary intense.  Chem Lit is easy, but it's just going to be a lot of work to do the research for my paper on Stellar Chemical evolution.   The class that is probably the most interesting, and the one in which I'm learning the most is Analytical Chem....which is a class about techniques, and more importantly Chemical Statistical Analysis.  Yeesh.

Thankfully, this book is saving my life.

 I've never taken a statistics class before, so the math is all new to me.  I get it, but it just takes some extra effort to put things together.  And, thank god, Excel does most of the work for me.  I've fiddled with that program for 10-15 years or so, but now I am learning the ins and outs like nobody's business.

Warning!  Science Ahead!

This weeks experiment was "Statistical Evaluation of Acid-Base Indicators".  The actual lab portion was your standard titration of a base Tris hydroxymethyl aminomethane "Tris" for short. (HOCH₂)₃CNH₂ 

_{This happy little fellow}

Measure out ~0.4260 grams, slap it in a flask, and then add about 20mL of Hydrochloric acid, then add a couple of drops of the indicator you are working with. The indicator being a liquid that changes color based on the pH level of the solution it is added to, so that you know if that solution has changed from basic to acidic conditions or vice-versa.  You then slowly, very, very slowly continue adding the acid to the flask until the indicator "Changes Color".  I put that in quotes because whatever genius designed these things, pretty much ensured that you can't tell the starting color from the final color.  An entire lab full of students whispering to each other "Does that look greenish-yellow, or yellowish-green to you?"  You then take a reading of how much acid you added to make the indicator change and write it down in your lab book.

You then repeat this entire process 20 MORE TIMES.

Yes, this is the allure and excitement of Science.  But the fun is only beginning!  Lab is over, and you go on your merry way (with your cap at a rakish angle).  Time to sit down and analyze your and everyone's data.

First you sit down and make a nice little table in Excel to put all your calculations in.

1. Go through everyone's data and arrange it by what particular indicator they were using.
2. Then convert the volume of the acid used in one titration to the number of moles of HCl.  Used 33.25 mL of HCl? 33.25 mL/1000 (Converts to Liters) * 36.458 grams/mol (Molecular mass of HCl) = 1.2130 moles of HCl     Voila!
3. Compute the mean (average) of all the moles of HCl, per student group, per indicator.
4. Compute the standard deviation of the data, again, per student group, per indicator.
5. Start a pot of coffee.
6. Go back and subject every data point, again Moles of HCl, to the Grubbs test to see if you have any erroneous outlier data points.  |data point - mean| / standard deviation.  If the value you get is larger than the value on the chart, based on the number of observations, compared to a 95% confidence...then you chuck that bit of data to the curb.
7. Go back and recalculate the mean, and standard deviation as before for each set, but leaving out your bad data.
8. Start another pot of coffee.
9. Calculate the combined mean Molarity and standard deviations for ALL data points of a given indicator.
10. Calculate the Relative standard deviation for each indicator.
11. Find the indicators that are farthest apart in terms of Mean HCl molarity, and subject them to the 'F' test to see if the average molarities are significantly different from each other at the 95% confidence level.  Are they?  No?  Good.
12. Calculate the pooled standard deviation for each indicator.  This bastard...

   13.  Seriously consider switching your major...decide to blog about it instead.

Call me bat-shit crazy...but I do love this stuff.

‎"Ah, there's nothing more exciting than science. You get all the fun of sitting still, being quiet, writing down numbers, paying attention... Science has it all." - Principal Skinner

I guess I will write up the actual report tomorrow.