Purity, formulations, chromatography and Rf values

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By the end you’ll be able to

define a pure substance as a single element or single compound not mixed with any other substance, and distinguish purity from mixtures and formulations
define a formulation as a useful mixture designed as a product with components present in measured quantities to give required properties
explain how melting point and boiling point data can be used to assess purity, including that pure substances have sharp melting and boiling points while mixtures show a range

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interpret chromatograms to determine the number of substances present, identify whether samples are pure or mixtures, and compare unknowns with known reference substances

calculate and use $R_f$ values where required, using $$R_f=\frac{\text{distance moved by substance}}{\text{distance moved by solvent}}$$ and recognising that comparisons are valid only under the same conditions

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