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As a result of working through this topic students should know that:

• Many reactions can be reversed by changing the conditions.
• Changes of state such as melting and boiling can be reversed by freezing or condensing the substance.
• Water of crystallisation can be removed from a hydrated salt or added to an anhydrous salt.
• The decomposition of calcium carbonate is a reversible reaction.
• The hydrolysis of an ester is the reverse of the esterification reaction involving an alcohol and a carboxylic acid.