### Transcription and Diagram Explanation for Educational Website --- #### Image Overview The image displays two photographs of thin-layer chromatography (TLC) plates, labeled "B." Each plate consists of three lanes labeled A, B, and C. A ruler is placed alongside each plate for measurement purposes. #### Diagram Details 1. **Left Image:** - Three distinct spots are visible in each lane, which represent different chemical components. - The spots vary in size and position, indicating different travel distances up the plate. - A vertical ruler beside the plate is used for measuring the distance traveled by each spot, with numbers ranging from 2 to 8. 2. **Right Image:** - Similar to the left image, it shows three lanes with spots corresponding to different components. - The spots are encircled in red, showing clear separation. - A baseline is marked for reference with "SO," and lanes are labeled below as A, B, and C. --- #### Task Explanation **a) R\(_f\) Calculation:** - For each major spot in lanes A, B, and C, calculate the R\(_f\) value. - R\(_f\) (Retention Factor) is the ratio of the distance traveled by the compound to the distance traveled by the solvent front. - Accurate measurements must be taken from the base starting line to the center of each spot and from the base to the solvent front. - Show all calculations for credit. **b) Component Identification:** - Leverage the chemical structures of the three components: carvone, dihydrocarveol, and limonene. - Predict and match the relative order of their R\(_f\) values. - Explain the reasoning behind the assignment of each spot to these components based on their polarity and interaction with the stationary phase. --- This exercise aims to provide practical experience in chromatographic techniques, enabling students to understand the relationship between molecular structure and chromatographic behavior. **The Principal Components of Spearmint Oil** Spearmint oil comprises three main components: (R)-carvone, (1R,2R,4R)-dihydrocarveol, and (R)-limonene. Below are the structural formulas of these compounds: - **(R)-Carvone**: Displays a six-membered ring with a ketone functional group. - **(1R,2R,4R)-Dihydrocarveol**: Features a six-membered ring with an alcohol group. - **(R)-Limonene**: Contains a six-membered ring with a terminal alkene group. ### Experiment Description 1. **Thin Layer Chromatography (TLC) Analysis:** TLC was performed using the following samples: - Spearmint oil (SO) - Reference compounds: A/(R)-carvone, B/(1R,2R,4R)-dihydrocarveol, C/(R)-limonene **Materials and Methods:** - TLC plates coated in silica gel. - Solvent system: 10% ethyl acetate in hexanes. - Developing agent: Potassium permanganate, used to visualize compound spots. 2. **Photographic Analysis:** - Two versions of TLC plate photos are shown: - Original photo. - Marked-up photo with added labels and annotations. **Details of the Marked-up Photo:** - Lanes are labeled SO, A, B, and C (representing the samples). - Origin and solvent front lines are marked. - Circles highlight overlapping spots in the SO and A lanes, indicating the presence of multiple compounds. This analysis helps to identify and distinguish between the components of spearmint oil using the reference compounds.