Study Guide: CHEM1LD Experiments #3-4 (UCI)

Experiment #3&4
Study online at https://quizlet.com/_5pynbt

1. Main Objective We first synthesize aspirin. Then we determine its purity
through three tests: TLC, melting point, and Fe3+. Then
we did absorbance of five different solutions with varying
concentrations and one unknown.

2. Concentrations To find: M1V1=M2V2
of varying Where M1= mol of ASA from g/.25=0.00888M
solutions V1= changing (1mL, 2mL...etc.)
V2=0.100 L
M2=?

3. Concentrations 8.88x10(-5)
1.776 x10(-4)
2.664x10(-4)
3.552x10(-4)
4.44x10(-4)

4. Special Proce- -make sure to record abs for concentrations
dures

5. Beer's Law Abs. vs. Concentration (graph)
A=eCl

6. Percent Yield (exp. yield/ theor. yield)x100
exp yield= how much asa you made
theor. yield= sa obtained converted to moles of sa then to
asa (1:1) then to grams asa

7. Rf [Distance from the origin to the center of the TLC spot (cm)
/ Distance from the origin to the solvent front (cm)]

8. Exact Mass First find concentration of unknown by plugging in ab-
sorbance into the equation of the line from Beer's Law plot.
M=n(mol)/V(L)
V (mol)= 50 mL to .05L
n=?
Find n= concentration*volume
Then divide by .001 L-this will give you new concentration


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