Chemistry Blog

Tag Archive: Chemistry Demonstrations

Jul 25

Build Your Own Dye-Sensitized Solar Cell


DSSC schematic

In 1991 Brian O’Regan and Michael Gratzel published a paper titled “A low-cost, high-efficiency solar cell based on dye-sensitized colloidal TiO2 films.” This paper is the foundation for an entire branch of solar energy conversion research known as dye-sensitized solar cells (DSSC). The basic operation of a DSSC is summarized in the schematic below. In …

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Mar 19

Chemistry Lab Demonstrations: Homemade Breathylizers…Sorta


bromocresolgreen

*For more cool stories, pictures, and videos of chemistry demonstrations, click here* Undergrads were on spring break last week, so no lab last week.  This week, we performed the Jones oxidation of isoborneol to camphor.  The crude product was put in the bottom of a Hirsch funnel with a cold finger, and the product was …

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Mar 05

Chemistry Lab Demonstrations – Silver Mirror


hwe

*For more cool stories, pictures, and videos of chemistry demonstrations, click here* This week’s reaction was the HWE-modified Wittig reaction (and here) between para-anisaldeyhde and triethyl phosphonoacetate.  Saponification, followed by recrystallization of the acidified product gives nice needles of p-methoxycinnamic acid.  Funny thing, though, p-methoxycinnamic acid is supposed to be a white solid.  Half of …

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Feb 25

Chemistry Lab Demonstrations – Dehydrating Sugar


*For more cool stories, pictures, and videos of chemistry demonstrations, click here* This week, the organic chemistry lab I’m TA’ing dehydrated 2-methylcyclohexanol with phosphoric acid to give a mixture of 1- and 3-methylcyclohexene.  The product ratio was determined by GC analysis… At least it was supposed to be.  The students for the most part did …

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Feb 17

Chemistry Lab Demonstrations: Upsidedown Thunderstorm


*For more cool stories, pictures, and videos of chemistry demonstrations, click here* SN2 lab today.  Preparation of (2-methylphenoxy)acetic acid from o-cresol and sodium chloroacetate.  NaOH deprotonates cresol.  Add sodium chloroacetate and reflux.  SN2 reaction occurs.  Acidify, collect the precipitate, and recrystallize from water.  Unfortunately, today’s lab took a really long time.  I’m not sure why, …

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Feb 10

Chemistry Lab Demonstrations: Sodium Acetate Crystallization


*For more cool stories, pictures, and videos of chemistry demonstrations, click here* Recrystallization lab today.  Standard two-solvent recrystallization of an unknown carboxylic acid from ethanol/water.  My students did awesome – as far as I know everyone obtained crystals on the first try. The demo today was crystallization of sodium acetate from a supersaturated water solution.  …

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