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  • Benedict's reagent reacting with sugars. It is a blue coloured solution, which is a mixture containing copper sulphate. It is used in biochemistry as a test for the presence of sugars. It reacts with sugars, such as glucose, to form an orange precipitate.
    38413RKP.jpg
  • Paper Chromatography of Ink. Chromatography is an analytical process, which separates a compound into its constituent chemicals. Chromatography paper is dipped vertically in a solvent with the ink painted on it. Capillary action draws the solvent up through the paper and dissolves the ink. As the solvent travels up the paper it takes the various chemicals in the ink with it, separating them into a series of colored bands.
    38357RKP.jpg
  • Lithium burning in the flame of a bunsen burner producing a pink/red flame. The colour of the flame is caused by electrons that have been excited to a higher energy state. When they relax they emit energy in the form of a characteristic wavelength of light. The colour of the flame is different for different elements and can be used to identify unknown substances.
    38268RKP.jpg
  • Titration experiment to measure the volume of acid needed to neutralize an alkaline solution. The alkaline solution is in the conical flask (bottom centre) and its alkalinity is indicated by the use of phenolphthalein indicator from the bottle. This indicator turns pink in an alkaline solution and colourless in an acidic solution. The acid is in the burette, the volume-measuring apparatus held over the flask. The tap (lower centre) is used to add acid until a colourless solution forms at the reaction endpoint. This acid volume is compared to the known volume of alkali, giving information on reaction chemistry and chemical concentrations.
    38316RKP.jpg
  • Flame test. Potassium burning in the flame of a bunsen burner producing a lilac flame. The colour of the flame is caused by electrons that have been excited to a higher energy state. When they relax they emit energy in the form of a characteristic wavelength of light. The colour of the flame is different for different elements and can be used to identify unknown substances.
    38270RKP.jpg
  • Flame test. Barium burning in the flame of a bunsen burner producing a green flame. The colour of the flame is caused by electrons that have been excited to a higher energy state. When they relax they emit energy in the form of a characteristic wavelength of light. The colour of the flame is different for different elements and can be used to identify unknown substances.
    38265RKP.jpg
  • Benedict's reagent reacting with sugars. It is a blue coloured solution, which is a mixture containing copper sulphate. It is used in biochemistry as a test for the presence of sugars. It reacts with sugars, such as glucose, to form an orange precipitate.
    38414RKP.jpg
  • Sodium flame test. Positive result of a flame test for sodium (Na), producing a yellow colour. This is due to the excitation of electrons in the sodium by the heat of the flame. As these electrons lose their energy, they emit photons of yellow light. The colour of the flame is different for different elements and can be used to identify unknown substances. The metal compound being tested here is sodium chloride.
    38272RKP.jpg
  • Iodine test for starch. Test tubes before (left) and right (after) showing a black colour that is the positive result of the test for starch using iodine. The starch  is a long coiled molecule. Iodine combines with the starch and ends up in the coil, which is why the iodine turns from light brown to black.
    38352RKP.jpg
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