Two phases of chromatography - Mobile Phase, Stationary Phase, Define Mobile Phase - The solvent that moves through the paper, carrying different substances with it, Define Stationary Phase - Contained on the paper, Does not move through it, What causes the movement of the dots on the chromatography paper? - The different dissolved substances in a mixture are attracted to the two phases in different proportions. , Example of an item used as a solvent (aqueous) - Water - used as a solvent, Example of an items used as a solvent (non aqueous) - Alcohol - used as a solvent, What kind of substances can a paper chromatogram distinguish? - Pure and Impure substances, Pure substance produces how many dots? - Produces one dot, An impure substance produces how many spots? - Produces more than one dot, Analysis: Two substances are likely to be the same if - They produce the same number of spots, and these match in colour, What is the formula for R f value? - Distance travelled by substance/distance travelled by solvent, Why are the distances travelled by each spot were measured in mm, rather than in cm. - Measurements in millimetres are more precise than those in centimetres. They will give more precise Rf values., If the juice carton reads "pure orange juice" does that mean that the orange juice is pure from a chemical sense? - Not pure - it contains different substances mixed together, a pure substance consists only of ... - only one element, What does a  mixture consists of? - Two or more different substances, not chemically joined togehter, What does Rf stand for? - Retention factor, List one advantage of PC - simple, rapid, inexpensive compared to other chromatography methods, List one disadvantage of PC - Large quantity of sample can not be applied, complex mixture can not be separated, When was paper chromatography first introduced? - It was first introduced by German scientist Christian Friedrich Schonbein (1865), Cellulose layers in filter paper act as what phase? stationary or mobile - Contain moisture which acts as stationary phase, What phase are organic solvents/buffers used? - Mobile phase,

Crime Busters - Paper Chromatography

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