Explain separation using stationary and mobile phases.

In the subtopic Chromatography (A-level only), this AQA A-Level Chemistry 7405 learning objective focuses on explain separation using stationary and mobile phases. It belongs to Chromatography (A-level only), so revision should stay anchored to this exact subtopic rather than drifting into a generic GCSE-level chemistry summary. Approved keywords to use include mobile phase. Stationary phase. means the phase in chromatography that remains fixed in place while the mobile phase moves through it Avoid the mistake of students frequently miscalculate Rf values by not properly measuring the distance traveled by the substance relative to the solvent front; instead, use the formula Rf = distance traveled by the substance / distance traveled by the solvent front. Ensure both distances are measured from the same starting point For exam answers, remember that the stationary phase does not move, while the mobile phase carries the components of the mixture