Required practical 12: separate species by thin-layer chromatography.

In the subtopic A-level required practical activities, this AQA A-Level Chemistry 7405 learning objective focuses on required practical 12: separate species by thin-layer chromatography. It belongs to A-level practical endorsement and required practical activities, so revision should stay anchored to this exact subtopic rather than drifting into a generic GCSE-level chemistry summary. Approved keywords to use include required practical, rate, chromatography. Thin-layer chromatography. means a technique used to separate non-volatile mixtures by allowing them to move along a stationary phase with a mobile phase Avoid the mistake of students often confuse the Rf value calculation in thin-layer chromatography, incorrectly stating it as the distance traveled by the substance divided by the distance traveled by the solvent front without proper substitution; instead, to correctly calculate the Rf value, use the formula Rf = distance traveled by substance / distance traveled by solvent front. For example, if the substance travels 5 cm and the solvent front travels 10 cm, substitute these values into the formula: Rf = 5 cm / 10 cm = 0.5. Therefore, the Rf value is 0.5 For exam answers, practice setting up thin-layer chromatography (TLC) experiments to separate different species effectively