Trilogy – Chemistry – CHAPTER 8 – Chemical analysis - H Draw and label the chromatogram with the following words: solvent front start line samples chromatography paper separated dyes Describe the chemical tests for hydrogen, oxygen, carbon dioxide and chlorine. Describe the difference between pure and impure substances and state at least 3 separation methods. Describe how to calculate Rf values. KEY WORDS: Chromatography Rf value Stationary phase Mobile phase Pure Impure formulation ASSESSMENT: 1

Trilogy – Chemistry – CHAPTER 8 – Chemical analysis - H Draw and label the chromatogram with the following words: solvent front start line samples chromatography paper separated dyes Describe the chemical tests for hydrogen, oxygen, carbon dioxide and chlorine. Hydrogen – hold a burning splint in front of a test tube of a gas. It will give a squeaky pop if hydrogen is present. Oxygen – put a glowing splint inside a test tube of gas. It will relight if oxygen is present. Carbon dioxide – bubble the as through a solution of limewater. If carbon dioxide is present the limewater will turn milky. Chlorine – put damp litmus paper near to the gas. It will bleach / turn white is chlorine gas is present. Describe the difference between pure and impure substances and state at least 3 separation methods. Pure = a substance that has had nothing has been added to it Impure = a substance that has had something added to it Filtration, crystallisation, distillation, fractional distillation, chromatography Describe how to calculate Rf values. Measure the distance from the start line to the solvent line Measure the distance moved by the substance. Calculate the Rf value by dividing the distance moved by the substance by the distance move by the solvent. KEY WORDS: Chromatography Rf value Stationary phase Mobile phase Pure Impure formulation ASSESSMENT: 2