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Thin-layer chromatography (TLC) is a versatile, inexpensive, and rapid analytical separation technique available to the organic chemist. This inquiry-based experiment investigates the governing principles as to why and how the technique works. Students are led into expressing the position a sample travels in a systematic manner, the retention factor, R f. It is found that compounds that are hydrogen bond acceptors (ethers and esters) are less strongly absorbed by the silica surface and possess larger R f values. Compounds such as alcohols and carboxylic acids which are strong hydrogen bond donors and acceptors are more strongly absorbed by the surface and have smaller R f values. A qualitative TLC study is also performed on compounds possessing different functional groups. The order of increasing functional group polarity is observed to be: ether < ester < ketone < aldehyde < amine < alcohol < carboxylic acid and directly corresponds to their observed R f values. Knowledge gained in earlier sections is utilized by solving a simulated application where students run a reaction and monitor its progress by TLC. When TLC analysis shows all of the starting material is consumed and only product is present in the reaction mixture, the reaction should be stopped and the product isolated.

This article describes the philosophy of using toys to engage students of all ages in chemistry. Three toys, Shrinky Dinks, Happy birds, and Hand Boilers, are featured. For each, the chemical principles behind the toy are described and suggestions for hands-on activities for students are given. There are also some suggestions of how these toys can be integrated into the curriculum

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One of the most commonly used ingredients in over-the-counter acne treatments in cream, gel, and wash form is benzoyl peroxide. It is an anti-bacterial agent that kills the bacterium (Propionibacterium acne) involved in the formation of acne. The formulation of these products is extremely difficult owing to the instability of benzoyl peroxide. Benzoyl peroxide is soluble in polyethylene glycol (PEG) and isopropyl myristate, but it is not stable in these solvents. Also, it is practically insoluble in water and only slightly soluble in ethanol but is very stable in the presence of these solvents. The stability of benzoyl peroxide in PEG or isopropyl myristate is increased upon addition of water or ethanol. Students take on the role of the process chemist and use peroxide strips to investigate the stability of benzoyl peroxide in an over-the-counter acne medication in solutions of water, ethanol, PEG, 50:50 ethanol:PEG, 50:50 water:PEG, isopropyl myristate, and 50:50 ethanol:isopropyl myristate.