Reversible and Irreversible Changes

Chemical changes come in two important types:

1. Reversible Changes – This is when materials can be changed back to how they were before the reaction took place.

E.g. When ice melts to form water. It could be frozen back to ice again.

2. Irreversible Changes – This is when materials cannot be changed back to how they were before.

E.g. When a pice of wood is burned to form ash. It cannot be made wood again.

See the PowerPoint below for some more examples.

Separating mixtures can be done by:

1. Sieving – when 2 solids are mixed

2. Filtration – when a solid and a liquid are mixed

3. Evaporation – when a solid is dissolved in a liquid

Follow these hyperlinks to learn more:-

  1. BBC Videos on Changes
  2. BBC Changes of State information
  3. Revision Quiz on Chemical Changes

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