The problem of determining our concentration!
Our refractive index measurements for the alcohol were not linear.
I went to the following web site and found data:
http://www.thewhiskystore.de/experts/alcohol.htm
You want to use this data as I did. Look how a RI gives two possibilities. You can figure it out by looking at the density.
Excell file : known
In our RI calculation we saw y = -0.0575x
2
+ 0.0873x + 1.3323. To use the quadratic equation, we need to make the left side equal to zero. Plug your RI into y and then subtract from both sides to make the left side equal zero.
RI of sample = 1.3650
1.3650 = -0.0575x
2
+ 0.0873x + 1.3323.
0 = -0.0575x
2
+ 0.0873x -.0327
Plug into the quadratic equation at
http://www.math.com/students/calculators/source/quadratic.htm
Hmm. Which is right? Make a reasonable guess.
If your sample is 31.2 % ethanol, then 1.00g of our sample = 0.312g of EtOH
The aliquat ratio is 200 mL total/4 mL we used.
% yield is actual /theoretical x 100%.