"Physical Vs Chemical Reactions" Return to list of pracs

Aim: This is to illustrate the difference between physical and chemical reactions.

Equipment: The equipment includes...  

• frying pan.
• materials such as ice, chocolate, candle wax, butter, cheese and sugar.

Method: Heat the different materials separately in a frying pan and observe whether they go through a physical or chemical reaction.

Background knowledge: A physical reaction is one that allows the substance to return easily to its original state (eg. ice melting and then freezing it again back to ice). Some of the above materials will melt and therefore can return upon cooling back to their original state (eg. butter, candle wax and ice) whereas some will burn. The process of burning is when a substance is heated the chemical structure changes permanently and no amount of cooling will return it back to its original state (eg. cheese will go brown and then burn; sugar will turn to toffee and then burn). Plastics are of two forms also - thermoplastics or ...