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How to Demonstrate the ‘Black Snake’ Exothermic Reaction

How to Demonstrate the ‘Black Snake’ Exothermic Reaction

In this short video, Stacey Wheeler will show how to demonstrate the ‘Black Snake’, a version of an exothermic reaction, which is a concept often covered as part of the GCSE Chemistry topic on energy changes during chemical reactions. It is important to understand exothermic changes as they have practical applications and are relevant to various topics, including energy transfers, chemical reactions, and thermodynamics.

You will need:

      • 100ml beaker half filled with normal sugar
      • 20ml concentrated sulfuric acid
      • A measuring cylinder
      • A fume cupboard or cabinet
      • Safety googles and gloves
      • Heatproof mat


  1. Stand your beaker, half full with sugar on your heatproof mat in the fume cabinet.
  2. Turn the fume cabinet on.
  3. Slowly pour in the concentrated sulfuric acid.
  4. Step back and observe the reaction.
  5. To dispose of this allow the beaker to cool, it is a good idea to leave the fume cabinet tuners on, precaution.
  6. Wearing gloves, remove the solid from the beaker and place in a bowl of cold water.
  7. Once rinsed, wrap the solid in newspaper and place in the waste bin.
  8. Step back and observe the reaction.

All health and safety measures are the responsibility of the teacher doing the demonstration. It is suggested that you practice before demonstration in front of a class.

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